Conservation of Momentum Review

A 20 kg lab cart collides with a 10 kg lab cart that is at rest. How does the magnitude of the total momentum after the collision compare to the magnitude of the total momentum before the collision?

• The momentum is greater before

• The momentum is greater after

• The momentum is the same both before and after

• There's not enough information to answer

In the diagram below, scaled vectors represent the momentum of each of two masses, A and B, sliding toward each other on a frictionless, horizontal surface. Which scaled vector best represents the momentum of the system after the masses collide?

• 1

• 2

• 3

• 4

A student with horizontal velocity v₁ jumps onto a stationary skateboard. After landing on the skateboard, the student and the skateboard move with velocity v₂ . Compared to velocity v₁ , velocity v₂ has

• the same magnitude and the same direction

• the same magnitude and the opposite direction

• smaller magnitude and the same direction

• larger magnitude and the same direction

A cue ball of mass .25 kg moves to the right at 2.0 m/s. It collides with an 8 ball of equal mass that is at rest. After the collision the cue ball comes to a stop. What is the speed of the 8 ball after the collision?

• 0 m/s

• 2.0 m/s

• 1.0 m/s

• 4 m/s

Two blocks moving in opposite directions collide and stick together after the collision. What is their combined speed after the collision?

• 16. m/s

• 2.0 m/s

• 4.0 m/s

• 7.0 m/s

A .01 kg bullet is fired from a stationary rifle of mass 4 kg. The bullet leaves the rifle with a velocity of 300 m/s right. What is the magnitude of the recoil velocity of the gun?

• 0 m/s

• 600 m/s

• .75 m/s

• 7.5 m/s

A 6000 kg railroad car moving at 5 m/s collides into a stationary car with a mass of 4000 kg. If they couple together after the collision, what will be the magnitude of their combined velocity immediately after impact?

The diagram below shows an 8.0-kilogram cart moving to the right at 4.0 meters per second about to make a head-on collision with a 4.0-kilogram cart moving to the left at 6.0 meters per second. After the collision, the 4.0-kilogram cart moves to the right at 3.0 meters per second. What is the velocity of the 8.0-kilogram cart after the collision?

• 0.50 m/s left

• 0.50 m/s right

• 5.5 m/s left

• 5.5 m/s right

A 3.0-kilogram steel block is at rest on a frictionless horizontal surface. A 1.0-kilogram lump of clay is propelled horizontally at 6.0 meters per second toward the block as shown in the diagram below. Upon collision, the clay and steel block stick together and move to the right with a speed of

• 1.5 m/s

• 2.0 m/s

• 3.0 m/s

• 6.0 m/s

Granny is skating and scoops up her grandchild. What is their final velocity once she picks up the child?