Gurumuda Networks
2 Work-energy principle Nonconservative force Motion on inclined plane with friction – Problems and Solutions
1. A block slides down an inclined plane with friction. What is the block’s velocity when the block hits the ground? The coefficient of kinetic friction is 0.4. Acceleration due to gravity is 10 m/s2.
Known :
Initial height (ho) = 6 m
Final height (ht) = 0 m
Initial speed (vo) = 0 (block initially at rest)
Coefficient of kinetic friction (μk) = 0.4
Work done in thermodynamics process – problems and solutions
1. An ideal gas is compressed from state 1 to state 2 as shown in the graph below. Determine the work done by the gas.
Solution
1 liter = 0.001 m3
Known :
Pressure 1 (P1) = 10 kPa = 10,000 Pa = 10,000 N/m2
Pressure 2 (P2) = 20 kPa = 20,000 Pa = 20,000 N/m2
Collision and conservation of mechanical energy – probems and solutions
1. Two objects have the same mass, m1 = m2 = 0.5 kg dropped from the same height as shown in the figure below. The radius of the circle is 1/5 m. The collision between both objects is perfectly elastic. Determine the velocity of each object after the collision. Acceleration due to gravity is 10 m/s2.
Known :
Mass of object (m) = m1 = m2 = 0.5 kg
Initial height (h1) = 1/5 m
Final height (h2) = 0 (base of path)
Momentum Impulse and Projectile motion – Problems and Solutions
1. A 0.2-kg ball will be inserted into hole C, as shown in the figure below. Hitter strikes the ball in 0.01 second and the path of B-C traveled in 1 second. Determine the magnitude of the force so the ball can be inserted into hole C. Acceleration due to gravity is 10 m/s2.
Known :
Angle (θ) = 60o
Mass of ball (m) = 0.2 kg
Acceleration due to gravity (g) = 10 m/s2
Time interval (Δt) = 0.01 second
Nonuniform linear motion – problems and solutions
1.
The table above shows data of three objects that travel the same distance at constant acceleration.
What are the final speed of object P and the initial speed of object Q?
Kinetic theory of gas and first law of thermodynamics – problems and solutions
1. Ideal gases are in a container with a volume of 4 liters and its pressure is 3 atm (1 atm = 105 N.m-2). The ideal gases heated at a constant pressure from 27oC to 87oC. The heat capacity of the gas is 9 J.K-1. What is the final volume of gases and the change of internal energy of gases?
Solution
Isobaric process (constant pressure)
Known :
The initial volume of gas (V1) = 4 liters
Rotation of rigid bodies – problems and solutions
The moment of force
1. Three forces act on a beam with a length of 6 meters, as shown in the figure below. What is the net torque rotates the beam about the point O as the axis of rotation?
Known :
The axis of rotation at point O.
Force 1 (F1) = F
The distance between the line of action of F1 with the axis of rotation (r1) = 3 meters
Springs in series and parallel – problems and solutions
1. A 160-gram object attaches at one end of a spring and the change in length of the spring is 4 cm. What is the change in length of three springs connected in series and parallel, as shown in the figure below?
Known :
The change in length of a spring (Δx) = 4 cm = 0.04 m
Mass (m) = 160 gram = 0.16 kg
Acceleration due to gravity (g) = 10 m/s2
Dynamics of rotational motions – problems and solutions
1. A pulley with the moment of inertia I = 2/5 MR2 has a mass of 2-kg. If the moment of force on the pulley is 4 N.m then what is the linear acceleration of the pulley. Acceleration due to gravity is g = 10 m.s-2.
Known :
The moment of inertia of the pulley (I) = 2/5 MR2
Mass of pulley (M) = 2 kg
Moment of force (τ) = 4 Nm
Dynamics of particles – problems and solutions
1. Object A with a mass of 6-kg and object B with a mass of 4-kg connected by a cord and pulled by a force of F = 60 N, as shown in the figure below. The coefficient of kinetic friction between the floor and both objects is 0.5 (tan θ = ¾). Acceleration due to gravity is 10 m/s2. What is the magnitude of the tension force?
Known :
Mass of object A (mA) = 6 kg
Mass of object B (mB) = 4 kg
Force (F) = 60 Newton