Semseter 2 Review

What are the differences between elastic and inelastic collisions?

• In elastic collisions, kinetic energy is conserved; in inelastic collisions, it is not.

• In elastic collisions, objects stick together; in inelastic collisions, they bounce apart.

• In elastic collisions, momentum is conserved; in inelastic collisions, it is not.

• In elastic collisions, objects will always permanently change shape; in inelastic collisions, objects do not change shape.

An object has a mass of 2 kg and is moving with a velocity of 3 m/s north. A second 4 kg object moves 4 m/s south. What is the total momentum of the system?

• 14 kg·m/s north

• 14 kg·m/s south

• 10 kg·m/s south

• 4 kg·m/s north

A boy with a mass of 120 kg traveling 2 m/s jumps on a stationary skateboard. Both the boy and the skateboard are free to roll in any direction. They stick together after the collision and move. What other information is needed to determine the final velocities of the boy and board?

• The friction between the boy and the skateboard

• The mass of the skateboard

• The height of the jump

• The angle at which the boy jumps

The momentum change of an object is equal to the _________.

• net force applied to it

• change in its velocity

• impulse applied to it

• acceleration it experiences

A 0.50 kg Ping-Pong ball is fired from a 2 kg Ping-Pong launcher. Compared to the impulse on the ball, the impulse on the launcher is ____ (greater, equal, smaller) because ________.

• greater, the launcher exerts a larger force

• equal, impulses are equal in magnitude and opposite in direction

• smaller, the launcher has a larger mass

• greater, the ball moves faster

Determine the impulse applied to a 0.35 kg soccer ball that comes toward a player at 14 m/s and is kicked back in the direction it came from at 22 m/s.

• 7 kg·m/s

• 12.6 kg·m/s

• 4.2 kg·m/s

• 8 kg·m/s

A 1.0 kg chunk of putty moving at 1.0 m/s collides and sticks to a 5 kg bowling ball that is initially at rest. What is the magnitude of the momentum of the ball and putty after the collision?

• 1.0 kg·m/s

• 5.0 kg·m/s

• 6.0 kg·m/s

• 0.17 kg·m/s

A golf club hits a stationary 0.050-kilogram golf ball with an average force of 5000 newtons, accelerating the ball to a speed of 44 meters per second. What is the magnitude of the impulse imparted to the ball by the golf club?

• 2.20 Ns

• 880 Ns

• 1100 Ns

• 220000 Ns

A tennis player's racket applies an average force of 200 newtons to a tennis ball for 0.025 second. The impluse exerted on the racket by the tennis ball is

• 0.025 Ns

• 5.0 Ns

• 200 Ns

• 80.0 Ns

Select all energies in the system at point A

• Gravitational energy

• Kinetic energy

• Elastic energy

• Linear energy

• None