Momentum and Conservation of Momentum

While playing pool, the white cue ball strikes the 8 ball. Before the collision, the cue ball's velocity was 10 m/s and the 8 ball was at rest. If both ball's have a mass of 0.15 kg and the cue ball's velocity after the collision is 2 m/s, what is the 8 ball's velocity?

• 2 m/s
• 8 m/s
• -2 m/s
• 1.5 m/s

In a physics experiment, two carts of mass 1.5 kg each are rolled towards each other.  The orange cart has a velocity of 2 m/s and the blue cart has a velocity of -1m/s.  The carts stick together when they collide.  Calculate their final speed.

• 0.5 m/s
• 1.0 m/s
• 0.33 m/s
• 0.67 m/s

Two football players with mass 75 kg and 100 kg run directly toward each other with speeds of 6 m/s and 8 m/s respectively. If they grab each other as they collide, the combined speed of the two players just after the collision would be:

• 2 m/s 
• 3.4 m/s 
• 4.6 m/s 
• 7.1 m/s

A large box slides across a frictionless surface with a velocity of 12 m/s and a mass of 4 kg,  collides with a smaller box with a mass of 2 kg that is stationary.  The boxes stick together. What is the velocity of the two combined masses after collision?

• 0 m/s
• 4 m/s
• 8 m/s
• 12 m/s

A 5 N force is applied to a 3 kg ball to change its velocity from +9 m/s to +3 m/s. The impulse on the ball is ______ N s.

• -2.5

• -10

• -18

• -45

The total momentum before a collision is _________ the total momentum after a collision.

• equal to 
• less than 
• more than
• It depends on the type of collision

A 120 kg lineman moving at -2 m/s tackles an 80 kg fullback moving at +8 m/s. If the fullback's velocity after they collide is +2 m/s, what is the lineman's velocity?

• 2 m/s
• 8.7 m/s
• 4.7 m/s
• 6 m/s

A 3,000 kg truck moving at +10 m/s hits a 1,000 kg parked car which moves off at +15 m/s. What is the velocity of the truck?

• 10 m/s
• 0 m/s
• 5 m/s
• 2 m/s

In any collision (crash) the ______ is ALWAYS constant

• Total Momentum
• total speed
• total Velocity
• Energy

The recoil speed of a rifle is much less than the exit velocity of a bullet because...

• the rifle experiences a smaller force
• the rifle experiences a smaller change in momentum
• the rifle has a much greater mass
• the rifle does not obey the laws of physics