{"id":167,"date":"2018-01-17T11:20:38","date_gmt":"2018-01-17T03:20:38","guid":{"rendered":"https:\/\/gurumuda.net\/physics\/?p=167"},"modified":"2018-01-17T11:20:38","modified_gmt":"2018-01-17T03:20:38","slug":"newtons-second-law-of-motion-problems-and-solutions","status":"publish","type":"post","link":"https:\/\/gurumuda.net\/physics\/newtons-second-law-of-motion-problems-and-solutions.htm","title":{"rendered":"Newton&#8217;s second law of motion \u2013 problems and solutions","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"<p align=\"justify\"><a href=\"https:\/\/gurumuda.net\/physics\/newtons-second-law-of-motion-problems-and-solutions.htm\" target=\"_blank\" rel=\"noopener\">Solved problems in Newton&#8217;s laws of motion &#8211; Newton&#8217;s second law of motion\u00a0<\/a><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">1. A 1 kg object accelerated at a constant 5 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">. Estimate the net force needed to accelerate the object.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"><u>Known :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">Mass (m) = 1 kg<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"><a href=\"https:\/\/gurumuda.net\/physics\/constant-acceleration-problems-and-solutions.htm\" rel=\"noopener\">Acceleration<\/a> (a) = 5 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"><u>Wanted <\/u><\/span><\/span><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> : net force (\u2211F)<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"><u>Solution :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">We use Newton&#8217;s second law to get the net force.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\">\u2211<span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">F = m a <\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\">\u2211<span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">F = (1 kg)(5 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">) = 5 kg m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = 5 Newton<\/span><\/span><\/p>\n<p align=\"justify\"><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">2. <a href=\"https:\/\/gurumuda.net\/physics\/mass-and-weight-problems-and-solutions.htm\" rel=\"noopener\">Mass<\/a> of an object = 1 kg, net force \u2211F = 2 Newton. Determine the magnitude and direction of the object&#8217;s acceleration&#8230;. <\/span><\/span><\/p>\n<p align=\"justify\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-168\" src=\"https:\/\/gurumuda.net\/physics\/wp-content\/uploads\/2018\/01\/Newtons-second-law-of-motion-\u2013-problems-and-solutions-1.png\" alt=\"Newton's second law of motion \u2013 problems and solutions 1\" width=\"141\" height=\"52\" \/><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"><u>Known :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">Mass (m) = 1 kg<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">Net force (\u2211F) = 2 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"><u>Wanted<\/u><\/span><\/span><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> : The magnitude and direction of the acceleration (a)<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"><u>Solution :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">a = \u2211F \/ m<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">a = 2 \/ 1<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">a = 2 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">The direction of the acceleration = the direction of the net force (\u2211F)<\/span><\/span><\/p>\n<p align=\"justify\"><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">3. Object&#8217;s mass = 2 kg, F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">1<\/span><\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = 5 Newton, F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = 3 Newton. The magnitude and direction of the acceleration is&#8230;<\/span><\/span><\/p>\n<p align=\"justify\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-170\" src=\"https:\/\/gurumuda.net\/physics\/wp-content\/uploads\/2018\/01\/Newtons-second-law-of-motion-\u2013-problems-and-solutions-2-1.png\" alt=\"Newton's second law of motion \u2013 problems and solutions 2\" width=\"179\" height=\"54\" \/><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"><u>Known :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">Mass (m) = 2 kg<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">1<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = 5 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">2<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = 3 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"><u>Wanted :<\/u><\/span><\/span><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> The magnitude and direction of the acceleration (a)<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"><u>Solution :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">net force :<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\">\u2211<span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">F = F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">1<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> \u2013 F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">2<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = 5 \u2013 3 = 2 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">The magnitude of the acceleration :<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">a = \u2211F \/ m<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">a = 2 \/ 2<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">a = 1 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">Direction of the acceleration = direction of the net force = direction of F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">1<\/span><\/sub><\/p>\n<p align=\"justify\"><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">4. Object&#8217;s mass = 2 kg, F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">1<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = 10 Newton, F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">2<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = 1 Newton. The magnitude and direction of the acceleration is&#8230;<\/span><\/span><\/p>\n<p align=\"justify\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-171\" src=\"https:\/\/gurumuda.net\/physics\/wp-content\/uploads\/2018\/01\/Newtons-second-law-of-motion-\u2013-problems-and-solutions-3.png\" alt=\"Newton's second law of motion \u2013 problems and solutions 3\" width=\"143\" height=\"97\" \/><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"><u>Known :<\/u><\/span><\/span><\/p>\n<p align=\"justify\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-172\" src=\"https:\/\/gurumuda.net\/physics\/wp-content\/uploads\/2018\/01\/Newtons-second-law-of-motion-\u2013-problems-and-solutions-4.png\" alt=\"Newton's second law of motion \u2013 problems and solutions 4\" width=\"165\" height=\"110\" \/><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">Mass (m) = 2 kg<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">2<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = 1 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">1<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = 10 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">1x<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">1<\/span><\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> cos 60<\/span><\/span><sup><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">o<\/span><\/span><\/sup><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = (10)(0.5) = 5 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"><u>Wanted <\/u><\/span><\/span><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">: The magnitude and direction of the acceleration (a)<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"><u>Solution :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">Net force :<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\">\u2211<span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">F = F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">1x<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> \u2013 F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">2<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = 5 \u2013 1 = 4 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">The magnitude of the acceleration :<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">a = \u2211F \/ m<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">a = 4 \/ 2<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">a = 2 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">Direction of the acceleration = direction of the net force = direction of F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">1x<\/span><\/sub><\/p>\n<p align=\"justify\"><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">5. F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">1<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = 10 Newton, F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">2 <\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">= 1 Newton, m<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">1<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = 1 kg, m<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">2<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = 2 kg. The magnitude and direction of the acceleration is&#8230;<\/span><\/span><\/p>\n<p align=\"justify\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-173\" src=\"https:\/\/gurumuda.net\/physics\/wp-content\/uploads\/2018\/01\/Newtons-second-law-of-motion-\u2013-problems-and-solutions-5.png\" alt=\"Newton's second law of motion \u2013 problems and solutions 5\" width=\"243\" height=\"60\" \/><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"><u>Known :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">Mass 1 (m<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">1<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">) = 1 kg<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">Mass 2 (m<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">2<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">) = 2 kg<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">1<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = 10 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">2<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = 1 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"><u>Wanted <\/u><\/span><\/span><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">: The magnitude and direction of the acceleration (a)<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"><u>Solution :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">The net force :<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\">\u2211<span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">F = F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">1<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> \u2013 F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">2<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> = 10 \u2013 1 = 9 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">The magnitude of the acceleration :<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">a = \u2211F \/ (m<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">1<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\"> + m<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">2<\/span><\/sub><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">)<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">a = 9 \/ (1 + 2)<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">a = 9 \/ 3<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">a = 3 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: medium\">The direction of the acceleration = the direction of the net force = direction of F<\/span><\/span><sub><span style=\"font-family: Times New Roman,serif\">1<\/span><\/sub><\/p>\n<p align=\"justify\"><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">6. <\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">A 40-kg block accelerated by a force of 200 N. Acceleration of the block is 3 m\/<\/span><\/span><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">s<sup>2<\/sup>. Determine the magnitude of friction force experienced by the block.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">A. 15 N<img loading=\"lazy\" decoding=\"async\" class=\"alignright size-full wp-image-3204\" src=\"https:\/\/gurumuda.net\/physics\/wp-content\/uploads\/2018\/01\/Newtons-second-law-of-motion-\u2013-problems-and-solutions-7.png\" alt=\"Newton's second law of motion \u2013 problems and solutions 7\" width=\"216\" height=\"85\" \/><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">B. 40 N<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">C. 43 N<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">D. 80 N<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><u>Known :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Mass (m) = 40 kg<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Force (F) = 200 N<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Acceleration (a) = 3 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><u>Wanted:<\/u><\/span><\/span><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> <a href=\"https:\/\/gurumuda.net\/physics\/force-of-static-and-kinetic-friction-problems-and-solutions.htm\" target=\"_blank\" rel=\"noopener\">Friction force<\/a> (F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">g<\/span><\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">)<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><u>Solution :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">The equation of <a href=\"https:\/\/gurumuda.net\/physics\/newtons-second-law-of-motion-problems-and-solutions.htm\" target=\"_blank\" rel=\"noopener\">Newton&#8217;s second law of motion<\/a><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\">\u2211<span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">F = m a<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\">\u2211<span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><i>F = net force, m = mass, a = acceleration<\/i><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">The direction of force F rightward, the direction of friction force leftward (the direction of friction force is opposite with the direction of object&#8217;s motion). <\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Choose rightward as positive and leftward as negative.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\">\u2211<span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">F = m a<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">F \u2013 F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">g<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> = m a<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">200 \u2013 F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">g<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> = (40)(3)<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">200 \u2013 F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">g<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> = 120<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">g <\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">= 200 \u2013 120<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">g <\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">= 80 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">The correct answer is D.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">7. Block A with a mass of 100-gram place above block B with a mass of 300 gram, and then block b pushed with a force of 5 N vertically upward. Determine the <a href=\"https:\/\/gurumuda.net\/physics\/normal-force-problems-and-solutions.htm\" target=\"_blank\" rel=\"noopener\">normal force<\/a> exerted by block B on block A.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">A. 1 N<img loading=\"lazy\" decoding=\"async\" class=\"alignright size-full wp-image-3198\" src=\"https:\/\/gurumuda.net\/physics\/wp-content\/uploads\/2018\/01\/Newtons-second-law-of-motion-\u2013-problems-and-solutions-2-2.png\" alt=\"Newton's second law of motion \u2013 problems and solutions 2\" width=\"102\" height=\"155\" \/><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">B. 1.25 N<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">C. 2 N<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">D. 3 N<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><u>Known :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Force (F) = 5 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Mass of block A (m<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">A<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">) = 100 gram = 0.1 kg <\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Mass of block B (m<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">B<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">) = 300 gram = 0.3 kg<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><a href=\"https:\/\/gurumuda.net\/physics\/acceleration-due-to-gravity-problems-and-solutions.htm\" target=\"_blank\" rel=\"noopener\">Acceleration of gravity<\/a> (g) = 10 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><a href=\"https:\/\/gurumuda.net\/physics\/gravitational-force-weight-problems-and-solutions.htm\" target=\"_blank\" rel=\"noopener\">Weight<\/a> of block A (w<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">A<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">) = (0.1 kg)(10 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">) = 1 kg m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> = 1 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Weight of block B (w<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">B<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">) = (0.3 kg)(10 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">) = 3 kg m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> = 3 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><u>Wanted :<\/u><\/span><\/span><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> Normal force exerted by block B to block A<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><u>Solution :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-3199\" src=\"https:\/\/gurumuda.net\/physics\/wp-content\/uploads\/2018\/01\/Newtons-second-law-of-motion-\u2013-problems-and-solutions-3-1.png\" alt=\"Newton's second law of motion \u2013 problems and solutions 3\" width=\"101\" height=\"176\" \/>There are several forces that act on both block, as shown in figure.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">F = push force (act on block B)<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">w<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">A<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> = weight of block A (act on block A)<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">w<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">B<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> = weight of block B (act on block B)<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">N<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">A<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> = normal force exerted by block B on block A (Act on block A)<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">N<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">A<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">\u2019 = normal force exerted by block A on block B (Act on block B)<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Apply Newton&#8217;s second law of motion on both blocks :<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\">\u2211<span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">F = m a<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">F \u2013 w<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">A<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> \u2013 w<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">B<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> + N<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">A<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> \u2013 N<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">A<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">\u2019 = (m<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">A<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> + m<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">B<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">) a<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><i>N<\/i><\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\"><i>A<\/i><\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><i> and N<\/i><\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\"><i>A<\/i><\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><i>\u2019 are action-reaction forces that have the same magnitude but opposite in direction so eliminated from the equation.<\/i><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">F \u2013 w<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">A<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> \u2013 w<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">B<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> = (m<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">A<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> + m<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">B<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">) a<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">5 \u2013 1 \u2013 3 = (0.1 + 0.3) a<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">5 \u2013 4 = (0.4) a<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">1 = (0.4) a<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">a = 1 \/ 0.4<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">a = 2.5 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Apply Newton&#8217;s second law of motion on block A :<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\">\u2211<span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">F = m a<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">N<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">A<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> \u2013 w<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">A<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> = m<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">A<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> a<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">N<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">A<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> \u2013 1 = (0.1)(2.5)<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">N<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">A<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> \u2013 1 = 0.25<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">N<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">A<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> = 1 + 0.25<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">N<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">A<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> = 1.25 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">The correct answer is B.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">8. An object with weight of 4 N supported by a cord and pulley. A force of 2 N acts on the block and one end of the cord pulled by a force of 9 N. Determine the net force acts on object X.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">A. 3 N upward<img loading=\"lazy\" decoding=\"async\" class=\"alignright size-full wp-image-3200\" src=\"https:\/\/gurumuda.net\/physics\/wp-content\/uploads\/2018\/01\/Newtons-second-law-of-motion-\u2013-problems-and-solutions-4-1.png\" alt=\"Newton's second law of motion \u2013 problems and solutions 4\" width=\"98\" height=\"147\" \/><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">B. 4 N downward<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">C. 9 N upward<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">D. 9 N downward<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><u>Known :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Weight of X (w<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">X<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">) = 4 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Pull force (F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">x<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">) = 2 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Tension force (F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">T<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">) = 9 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><u>Wanted:<\/u><\/span><\/span><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> Net force acts on object X<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><u>Solution :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Vertically upward forces that act on object X :<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">The tension force has the same magnitude in all part of the cord. So the tension force is 9 N.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Vertically downward forces that act on object X :<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">There are two forces that act on object X and both forces are vertically downward, the horizontal component of weight w<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">x<\/span><\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> and the horizontal component of force F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">x<\/span><\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Net force act on the object X :<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">T<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> \u2013 w<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">X<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> \u2013 F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">x <\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">= 9 \u2013 4 \u2013 2 = 9 \u2013 6 = 3 <\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">The net force act on the object X is 3 Newton, vertically upward.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">The correct answer is A.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">9. An object initially at rest on a smooth horizontal surface. A force of 16 N acts on the object so the object accelerated at 2 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">. If the same object at rest on a rough horizontal surface so the friction force acts on the object is 2 N, then determine the acceleration of the object if the same force of 16 N acts on the object.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">A. 1.75 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">B. 1.50 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">C. 1.00 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">D. 0.88 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><u>Known :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Force (F) = 16 Newton = 16 kg m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Acceleration (a) = 2 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Friction force (F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">fric<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">) = 2 Newton = 2 kg m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><u>Wanted :<\/u><\/span><\/span><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> Object&#8217;s acceleration ?<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><u>Solution :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\">Smooth horizontal surface (no friction force) :<\/span><\/p>\n<p class=\"western\" align=\"justify\"><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-3201\" src=\"https:\/\/gurumuda.net\/physics\/wp-content\/uploads\/2018\/01\/Newtons-second-law-of-motion-\u2013-problems-and-solutions-5-1.png\" alt=\"Newton's second law of motion \u2013 problems and solutions 5\" width=\"174\" height=\"74\" \/>\u2211<span style=\"font-family: Times New Roman, serif\">F = m a<\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\">F = m a<\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\">16 = (m) 2<\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\">m = 16 \/ 2<\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\">m = 8 kg<\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Mass of object is 8 kilogram.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\">Rough horizontal surface (there is a friction force) :<\/span><\/p>\n<p class=\"western\" align=\"justify\"><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-3202\" src=\"https:\/\/gurumuda.net\/physics\/wp-content\/uploads\/2018\/01\/Newtons-second-law-of-motion-\u2013-problems-and-solutions-6.png\" alt=\"Newton's second law of motion \u2013 problems and solutions 6\" width=\"171\" height=\"73\" \/>\u2211<span style=\"font-family: Times New Roman, serif\">F = m a<\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\">F \u2013 F<\/span><sub><span style=\"font-family: Times New Roman, serif\">fric<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"> = m a<\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\">16 &#8211; 2 = 8 a<\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\">14 = 8 a<\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\">a = 14 \/ 8<\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\">a = 1.75 m\/s<\/span><sup><span style=\"font-family: Times New Roman, serif\">2<\/span><\/sup><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Object&#8217;s acceleration is 1.75 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">The correct answer is A.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">10. Tom and Andrew push an object on the smooth floor. Tom push the object with a force of 5.70 N. If the mass of the object is 2.00 kg and acceleration experienced by the object is 2.00 ms<\/span><\/span><sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">-2<\/span><\/span><\/sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">, then determine the magnitude and direction of force act by Tom.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">A. 1.70 N and its direction is opposite with force acted by Andre.w<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">B. 1.70 N and its direction same as force acted by Andrew<br \/>\n<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">C. 2.30 N and its direction is opposite with force acted by Andrew.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">D. 2.30 N and its direction same as force acted by Andrew.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><u>Known :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Push force acted by Andrew (F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">1<\/span><\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">) = 5.70 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Mass of object (m) = 2.00 kg<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Acceleration (a) = 2.00 m\/s<\/span><\/span><sup><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sup><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><u>Wanted :<\/u><\/span><\/span><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> Magnitude and direction of force acted by Tom (F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">2<\/span><\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">) ?<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"><u>Solution :<\/u><\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Apply Newton&#8217;s second law of motion :<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\">\u2211<span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">F = m a<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">1<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> + F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">2<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> = m a<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">5.70 + F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">2<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> = (2)(2)<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">5.70 + F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">2<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> = 4<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">2<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> = 4 \u2013 5.70<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">2<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\"> = &#8211; 1.7 Newton<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">Minus sign indicated that (F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">2<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">) is opposite with push force act by Andrew (F<\/span><\/span><sub><span style=\"font-family: Times New Roman, serif\">1<\/span><\/sub><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">).<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\"><span style=\"font-family: Times New Roman, serif\"><span style=\"font-size: medium\">The correct answer is A.<\/span><\/span><\/p>\n<p class=\"western\" align=\"justify\">11. If the mass of the block is the same, which figure shows the smallest acceleration?<\/p>\n<p align=\"justify\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-medium wp-image-2872\" src=\"https:\/\/gurumuda.net\/physics\/wp-content\/uploads\/2018\/05\/Newtons-first-law-and-Newtons-second-law-2-300x92.png\" alt=\"Newton's first law and Newton's second law 2\" width=\"300\" height=\"92\" srcset=\"https:\/\/gurumuda.net\/physics\/wp-content\/uploads\/sites\/28\/2018\/05\/Newtons-first-law-and-Newtons-second-law-2-300x92.png 300w, https:\/\/gurumuda.net\/physics\/wp-content\/uploads\/sites\/28\/2018\/05\/Newtons-first-law-and-Newtons-second-law-2.png 373w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/p>\n<p class=\"western\" align=\"justify\">Solution<\/p>\n<p class=\"western\" align=\"justify\">Net force A :<\/p>\n<p class=\"western\" align=\"justify\">\u03a3F = 4 N + 2 N \u2013 3 N = 6 N \u2013 3 N = 3 Newton, leftward<\/p>\n<p class=\"western\" align=\"justify\">Net force B :<\/p>\n<p class=\"western\" align=\"justify\">\u03a3F = 2 N + 3 N \u2013 4 N = 5 N \u2013 4 N = 1 Newton, rightward<\/p>\n<p class=\"western\" align=\"justify\">Net force C :<\/p>\n<p class=\"western\" align=\"justify\">\u03a3F = 4 N + 3 N \u2013 2 N = 7 N \u2013 2 N = 5 Newton, rightward<\/p>\n<p class=\"western\" align=\"justify\">Net force D :<\/p>\n<p class=\"western\" align=\"justify\">\u03a3F = 3 N + 4 N + 2 N = 9 Newton, rightward<\/p>\n<p class=\"western\" align=\"justify\">The equation of Newton&#8217;s second law :<\/p>\n<p class=\"western\" align=\"justify\">\u03a3F = m a<\/p>\n<p class=\"western\" align=\"justify\">a = \u03a3F \/ m<\/p>\n<p class=\"western\" align=\"justify\"><i>a = acceleration, \u03a3F = net force, m = mass<\/i><\/p>\n<p class=\"western\" align=\"justify\">Based on the above formula, the acceleration (a) is directly proportional to the net force (\u03a3F) and inversely proportional to mass (m). If the mass of an object is the same, the greater the resultant force, the greater the acceleration or the smaller the resultant force, the smaller the acceleration.<br \/>\nBased on the above calculation, the smallest net force is 1 Newton so the acceleration is also smallest.<\/p>\n<p class=\"western\" align=\"justify\">The correct answer is B.<\/p>\n<p align=\"justify\"><\/p>\n<p class=\"western\" align=\"justify\">12. Some forces act on an object with a mass of 20 kg, as shown in the figure below.<\/p>\n<p align=\"justify\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-2873\" src=\"https:\/\/gurumuda.net\/physics\/wp-content\/uploads\/2018\/05\/Newtons-first-law-and-Newtons-second-law-3.png\" alt=\"Newton's first law and Newton's second law 3\" width=\"242\" height=\"47\" \/><\/p>\n<p class=\"western\" align=\"justify\">Determine the object&#8217;s acceleration.<\/p>\n<p class=\"western\" align=\"justify\"><u>Known :<\/u><\/p>\n<p class=\"western\" align=\"justify\">Mass of object (m) = 20 kg<\/p>\n<p class=\"western\" align=\"justify\">Net force (\u03a3F) = 25 N + 30 N \u2013 15 N = 40 N<\/p>\n<p class=\"western\" align=\"justify\"><u>Wanted:<\/u> Acceleration of an object<\/p>\n<p class=\"western\" align=\"justify\"><u>Solution :<\/u><\/p>\n<p class=\"western\" align=\"justify\">Object&#8217;s acceleration calculated using the equation of Newton&#8217;s second law :<\/p>\n<p class=\"western\" align=\"justify\">\u03a3F = m a<\/p>\n<p class=\"western\" align=\"justify\">a = \u03a3F \/ m = 40 N \/ 20 kg = 2 N\/kg = 2 m\/s<sup>2<\/sup><\/p>\n<p align=\"justify\"><\/p>\n<p class=\"western\" align=\"justify\">13. Which statements below describes Newton&#8217;s third law?<\/p>\n<p class=\"western\" align=\"justify\">(1) Passengers pushed forward when the bus braked suddenly<\/p>\n<p class=\"western\" align=\"justify\">(2) B<span lang=\"en-US\">ooks on paper <\/span>are not falling<span lang=\"en-US\"> when the paper is pulled quickly<\/span><\/p>\n<p class=\"western\" align=\"justify\">(3) <span lang=\"en-US\">When playing skateboard when the foot pushes the ground back then the skateboard will slide forward<\/span><\/p>\n<p class=\"western\" align=\"justify\">(4) O<span lang=\"en-US\">ars pushed backward, boats moving forward<\/span><\/p>\n<p class=\"western\" align=\"justify\">Solution :<\/p>\n<p class=\"western\" align=\"justify\">(1) <a href=\"https:\/\/gurumuda.net\/physics\/newtons-first-law-of-motion-problems-and-solutions.htm\" target=\"_blank\" rel=\"noopener\">Newton&#8217;s first law<\/a><\/p>\n<p class=\"western\" align=\"justify\">(2) Newton&#8217;s first law<\/p>\n<p class=\"western\" align=\"justify\">(3) Newton&#8217;s third law<\/p>\n<p class=\"western\" align=\"justify\">(4) Newton&#8217;s third law<\/p>\n<p align=\"justify\">[wpdm_package id=&#8217;470&#8242;]<\/p>\n<ol>\n<li><a href=\"https:\/\/gurumuda.net\/physics\/mass-and-weight-problems-and-solutions.htm\" rel=\"noopener\">Mass and weight<\/a><\/li>\n<li><a href=\"https:\/\/gurumuda.net\/physics\/normal-force-problems-and-solutions.htm\" rel=\"noopener\">Normal force<\/a><\/li>\n<li><a href=\"https:\/\/gurumuda.net\/physics\/newtons-second-law-of-motion-problems-and-solutions.htm\" rel=\"noopener\">Newton&#8217;s second law of motion<\/a><\/li>\n<li><a href=\"https:\/\/gurumuda.net\/physics\/force-of-static-and-kinetic-friction-problems-and-solutions.htm\" rel=\"noopener\">Friction force<\/a><\/li>\n<li><a href=\"https:\/\/gurumuda.net\/physics\/motion-on-horizontal-surface-without-friction-force-application-of-newtons-law-of-motion-problems-and-solutions.htm\" rel=\"noopener\">Motion on the horizontal surface without friction force<\/a><\/li>\n<li><a href=\"https:\/\/gurumuda.net\/physics\/motion-of-two-bodies-with-the-same-accelerations-on-rough-horizontal-surface-with-friction-force-problems-and-solutions.htm\" rel=\"noopener\">The motion of two bodies with the same acceleration on the rough horizontal surface with the friction force<\/a><\/li>\n<li><a href=\"https:\/\/gurumuda.net\/physics\/motion-on-inclined-plane-without-friction-force-application-of-newtons-law-of-motion-problems-and-solutions.htm\" rel=\"noopener\">Motion on the inclined plane without friction force<\/a><\/li>\n<li><a href=\"https:\/\/gurumuda.net\/physics\/motion-on-rough-inclined-plane-with-friction-force-application-of-newtons-law-of-motion-problems-and-solutions.htm\" rel=\"noopener\">Motion on the rough inclined plane with the friction force<\/a><\/li>\n<li><a href=\"https:\/\/gurumuda.net\/physics\/application-of-newtons-law-of-motion-in-an-elevator-problems-and-solutions.htm\" rel=\"noopener\">Motion in an elevator<\/a><\/li>\n<li><a href=\"https:\/\/gurumuda.net\/physics\/bodies-connected-by-cord-and-pulley-application-of-newtons-law-of-motion-problems-and-solutions.htm\" rel=\"noopener\">The motion of bodies connected by cord and pulley<\/a><\/li>\n<li><a href=\"https:\/\/gurumuda.net\/physics\/two-bodies-with-the-same-magnitude-of-acceleration-application-of-newtons-law-of-motion-problems-and-solutions.htm\" rel=\"noopener\">Two bodies with the same magnitude of accelerations<\/a><\/li>\n<li><a href=\"https:\/\/gurumuda.net\/physics\/rounding-a-flat-curve-dynamics-of-cicular-motion-problems-and-solutions.htm\" rel=\"noopener\">Rounding a flat curve &#8211; dynamics of circular motion<\/a><\/li>\n<li><a href=\"https:\/\/gurumuda.net\/physics\/rounding-a-banked-curve-dynamics-of-cicular-motion-problems-and-solutions.htm\" rel=\"noopener\">Rounding a banked curve &#8211; dynamics of circular motion<\/a><\/li>\n<li><a href=\"https:\/\/gurumuda.net\/physics\/uniform-motion-in-a-horizontal-circle-problems-and-solutions.htm\" rel=\"noopener\">Uniform motion in a horizontal circle<\/a><\/li>\n<li><a href=\"https:\/\/gurumuda.net\/physics\/centripetal-force-in-uniform-circular-motion-problems-and-solutions.htm\" rel=\"noopener\">Centripetal force in uniform circular motion<\/a><\/li>\n<\/ol>\n<p class=\"western\" align=\"justify\"><!--more--><\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"<p>Solved problems in Newton&#8217;s laws of motion &#8211; Newton&#8217;s second law of motion\u00a0 1. A 1 kg object accelerated at a constant 5 m\/s2. Estimate the net force needed to accelerate the object. Known : Mass (m) = 1 kg Acceleration (a) = 5 m\/s2 Wanted : net force (\u2211F) Solution : We use Newton&#8217;s &#8230; <a title=\"Newton&#8217;s second law of motion \u2013 problems and solutions\" class=\"read-more\" href=\"https:\/\/gurumuda.net\/physics\/newtons-second-law-of-motion-problems-and-solutions.htm\" aria-label=\"Read more about Newton&#8217;s second law of motion \u2013 problems and solutions\">Read more<\/a><\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"","_seopress_social_fb_title":"","_seopress_social_fb_desc":"","_seopress_social_fb_img":"","_seopress_social_fb_img_attachment_id":0,"_seopress_social_fb_img_width":0,"_seopress_social_fb_img_height":0,"_seopress_social_twitter_title":"","_seopress_social_twitter_desc":"","_seopress_social_twitter_img":"","_seopress_social_twitter_img_attachment_id":0,"_seopress_social_twitter_img_width":0,"_seopress_social_twitter_img_height":0,"_seopress_redirections_value":"","_seopress_redirections_enabled":"","_seopress_redirections_enabled_regex":"","_seopress_redirections_logged_status":"","_seopress_redirections_param":"","_seopress_redirections_type":0,"_seopress_analysis_target_kw":"Newton&#039;s second law of motion \u2013 problems and solutions","_seopress_news_disabled":"","_seopress_video_disabled":"","_seopress_video":[],"_seopress_pro_schemas_manual":[],"_seopress_pro_rich_snippets_disable_all":"","_seopress_pro_rich_snippets_disable":[],"_seopress_pro_schemas":[],"footnotes":""},"categories":[3],"tags":[],"class_list":["post-167","post","type-post","status-publish","format-standard","hentry","category-solved-problems-in-basic-physics"],"gt_translate_keys":[{"key":"link","format":"url"}],"_links":{"self":[{"href":"https:\/\/gurumuda.net\/physics\/wp-json\/wp\/v2\/posts\/167","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gurumuda.net\/physics\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gurumuda.net\/physics\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gurumuda.net\/physics\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gurumuda.net\/physics\/wp-json\/wp\/v2\/comments?post=167"}],"version-history":[{"count":0,"href":"https:\/\/gurumuda.net\/physics\/wp-json\/wp\/v2\/posts\/167\/revisions"}],"wp:attachment":[{"href":"https:\/\/gurumuda.net\/physics\/wp-json\/wp\/v2\/media?parent=167"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gurumuda.net\/physics\/wp-json\/wp\/v2\/categories?post=167"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gurumuda.net\/physics\/wp-json\/wp\/v2\/tags?post=167"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}