AP Physics - Momentum

A truck moves along a frictionless level road at a constant speed.  The truck is open on top.  A large load of gravel is suddenly dumped into the truck.  The velocity of the truck:

• Increases.

• Remains the same.

• Decreases.

• Immediately goes to zero.

A car of mass m is moving with a momentum p.  How would you represent its kinetic energy in terms of these two quantities?

•   p²/2m

• ½ p²m

• pm

• pm/2

When a ping-pong  ball rolling with a speed of 3.0 m/s collides with a bowling ball at rest, the ping-pong's speed after the collision will be close to:

• 0 m/s

• 3.0 m/s

• 6.0 m/s

• 12 m/s

A bowling ball moving with speed, v collides head-on with a stationary tennis ball.  The collision is elastic, and there is no friction.  The bowling ball barely slows down.  What is the speed of the tennis ball after the collision?

• nearly v

• nearly 2v

• nearly 3v

• nearly 4v

A 3 kg ball is dropped onto a concrete floor. What is the magnitude of the ball’s change in momentum if its speed just before striking the floor is 7 m/s and its rebound speed is 3 m/s?

• 10 kg-m/s

• 15 kg-m/s

• 30 kg-m/s

• 60 kg-m/s

A 3.0 kg toy truck moves freely along a track at 2.0 m/s and collides with a 1.0 kg toy car that is at rest. After the collision, the two cars stick together. What is their velocity after the collision?

• 1.5 m/s

• 2.0 m/s

• 2.5 m/s

• 3.0 m/s

Two blocks are on a frictionless surface and have the same mass m.  Block 2 is initially at rest. Block 1 moves to the left with speed 4v and collides inelastically with block 2.  Which of the following choices is closest to the final speed of the system of two blocks?

• zero

• v

• 2v

• 4v

Two blocks are on a frictionless surface and have the same mass m.  Block 2 is initially at rest. Block 1 moves to the left with speed 4v and collides elastically with block 2.  What is the final speed of block 1?

• zero

• v

• 2v

• 4v

An object with a mass of 2.0 kg is accelerated from rest. The above graph shows the magnitude of the net force as a function of time. At t = 4.0 s the object’s velocity is closest to which of the following?

• 2.0 m/s

• 4.0 m/s

• 10 m/s

• 13 m/s

A carpenter is initially at rest on an icy pond when he decides to throw his hammer.  After being thrown, the hammer moves in one direction while the carpenter moves off in the opposite direction. Which of the following correctly describes this activity?

• The carpenter and the hammer will have the same kinetic energy.

• The hammer will have a greater magnitude of momentum.

• The carpenter will have a greater magnitude of momentum.

• The carpenter and the hammer will have equal and opposite momentum.