{"id":2829,"date":"2018-05-26T13:36:52","date_gmt":"2018-05-26T05:36:52","guid":{"rendered":"https:\/\/gurumuda.net\/physics\/?p=2829"},"modified":"2023-08-06T14:27:12","modified_gmt":"2023-08-06T14:27:12","slug":"kinetic-energy-problems-and-solutions","status":"publish","type":"post","link":"https:\/\/gurumuda.net\/physics\/kinetic-energy-problems-and-solutions.htm","title":{"rendered":"Kinetic energy \u2013 problems and solutions","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Kinetic energy \u2013 problems and solutions<\/span><\/span><\/p>\n

1. <\/span><\/span>Two cars have the same mass<\/a><\/span><\/span>, <\/span><\/span>moving with different kinetic energy. The kinetic energy<\/a> of the first car is 9 times the second car’s kinetic energy. The first car speed comparison with the second car is …..<\/span><\/span><\/p>\n

Known :<\/u><\/span><\/span><\/p>\n

Mass <\/span><\/span>of car A <\/span><\/span>(m<\/span><\/span>A<\/span><\/sub>) = m<\/span><\/span><\/p>\n

Mass of car B <\/span><\/span>(m<\/span><\/span>B<\/span><\/sub>) = m<\/span><\/span><\/p>\n

The kinetic energy of car <\/span><\/span>B (K<\/span><\/span>E<\/span><\/span>B<\/span><\/sub>) = K<\/span><\/span>E<\/span><\/span><\/p>\n

The kinetic energy of car A <\/span><\/span>(K<\/span><\/span>E<\/span><\/span>A<\/span><\/sub>) = 9 K<\/span><\/span>E<\/span><\/span><\/p>\n

Wanted:<\/u><\/span><\/span> The first car speed comparison with the second car<\/span><\/span><\/p>\n

Solution :<\/u><\/span><\/span><\/p>\n

The equation of kinetic energy :<\/span><\/span><\/p>\n

K<\/span><\/span>E<\/span><\/span> = 1\/2 m v<\/span><\/span>2<\/span><\/span><\/sup><\/p>\n

2 K<\/span><\/span>E <\/span><\/span>= m v<\/span><\/span>2<\/span><\/span><\/sup><\/p>\n

v<\/span><\/span>2 <\/span><\/span><\/sup>= 2 K<\/span><\/span>E<\/span><\/span> \/ m<\/span><\/span><\/p>\n

The speed of car <\/span><\/span>A :<\/span><\/span><\/p>\n

v<\/span><\/span>2 <\/span><\/span><\/sup>= 2 K<\/span><\/span>E<\/span><\/span>A<\/span><\/sub> \/ m<\/span><\/span>A <\/span><\/sub>= 2 (9 K<\/span><\/span>E<\/span><\/span>) \/ m = 18 K<\/span><\/span>E<\/span><\/span> \/ m<\/span><\/span><\/p>\n

The speed of car B <\/span><\/span>:<\/span><\/span><\/p>\n

v<\/span><\/span>2 <\/span><\/span><\/sup>= 2 K<\/span><\/span>E<\/span><\/span>B<\/span><\/sub> \/ m<\/span><\/span>B <\/span><\/sub>= 2 K<\/span><\/span>E<\/span><\/span> \/ m = 2 K<\/span><\/span>E<\/span><\/span> \/ m<\/span><\/span><\/p>\n

The comparison of the speed of car A and car B :<\/span><\/span><\/p>\n

18 K<\/span><\/span>E<\/span><\/span> \/ m : 2 K<\/span><\/span>E<\/span><\/span> \/ m<\/span><\/span><\/p>\n

18: 2<\/span><\/span><\/p>\n

9 : 1 = 3<\/span><\/span>2<\/span><\/span><\/sup> : 1<\/span><\/span>2<\/span><\/span><\/sup><\/p>\n

<\/p>\n

2. The kinetic energy of the object at point B<\/span> = 100 J. If the mass of the object is 2.5 kg<\/span>, then <\/span>determine <\/span>the kinetic energy of the object <\/span>when <\/span>it <\/span>strikes <\/span>the ground at point C<\/span>. Acceleration due to gravity<\/a> is 10 m\/s<\/span>2<\/span><\/sup>.<\/span><\/span><\/span><\/p>\n

Solution<\/span><\/span><\/p>\n

The kinetic energy of the object when it arrives at point B :\"Kinetic<\/span><\/span><\/span><\/p>\n

PE = m g h = (2.5)(10)(4) = 100 Joule<\/span><\/span><\/p>\n

The kinetic energy of the object when it arrives at point C :<\/span><\/span><\/span><\/p>\n

PE = m g h <\/span><\/span><\/p>\n

PE = (2.5)(10)(4 + 6) <\/span><\/span><\/p>\n

PE = (2.5)(10)(10) <\/span><\/span><\/p>\n

PE = 250 Joule<\/span><\/span><\/p>\n

<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

Kinetic energy \u2013 problems and solutions 1. Two cars have the same mass, moving with different kinetic energy. The kinetic energy of the first car is 9 times the second car’s kinetic energy. The first car speed comparison with the second car is ….. Known : Mass of car A (mA) = m Mass of … Read more<\/a><\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":0,"comment_status":"closed","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":"Kinetic energy \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-2829","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\/2829","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=2829"}],"version-history":[{"count":1,"href":"https:\/\/gurumuda.net\/physics\/wp-json\/wp\/v2\/posts\/2829\/revisions"}],"predecessor-version":[{"id":8541,"href":"https:\/\/gurumuda.net\/physics\/wp-json\/wp\/v2\/posts\/2829\/revisions\/8541"}],"wp:attachment":[{"href":"https:\/\/gurumuda.net\/physics\/wp-json\/wp\/v2\/media?parent=2829"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gurumuda.net\/physics\/wp-json\/wp\/v2\/categories?post=2829"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gurumuda.net\/physics\/wp-json\/wp\/v2\/tags?post=2829"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}