momentum

How do we define impulse?

• A force that is applied at random.

• A force that is applied only for a short period of time.

• Force multiplied by the time of impact

• The time interval that a force lasts.

A mosquito and a truck have a head-on collision. Splat! Which has a larger change of momentum?

• The mosquito

• The truck

• They have the same change of momentum.

• Can’t say without knowing their initial velocities.

A mosquito and a truck have a head-on collision. Splat! Which has a larger impulse applied to it?

• The mosquito

• The truck

• They have the same impulse.

• Can’t say without knowing their initial velocities.

In order to catch a ball, a baseball player naturally moves their hand backward in the direction of the ball's motion once the ball contacts the hand. This habit causes the force of impact on the player's hand to be reduced in size mostly because _____

• a resulting impact velocity has lessened

• the momentum change is decreased

• the time of impact is increased

• the time of impact is decreased

• none of the above

A light plastic cart and a heavy steel cart are both pushed with the same force for 1.0 s, starting from rest. After the force is removed, the momentum of the light plastic cart is ________ that of the heavy steel cart.

• Greater than

• Equal to

• Less than

• Can’t say. It depends on how big the force is.

The two boxes are sliding along a frictionless surface. They collide and stick together. Afterward, the velocity of the

two boxes is

• 2 m/s to the left

• 1 m/s to the left

• 0 m/s, at rest

• 1 m/s to the right

• 2 m/s to the right

The 1-kg box is sliding along a frictionless surface. It collides with and sticks to the 2-kg box. Afterward, the speed of the two boxes is

• 0 m/s

• 1 m/s

• 2 m/s

• 3 m/s

• There’s not enough information to tell.

A 4 kg object has a momentum of 12 kg-m/s. The object's speed is ______ m/s

• 3

• 4

• 12

• 48

• none of these

A 5-N force is applied to a 3-kg ball to change its velocity from +9 m/s to +3 m/s. How much did the ball's momentum change?

• -2.5 kg m/s

• -6 kg m/s

• -18 kg m/s

• -45 kg 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 is encountered by the ball for a time of _______ seconds.

• 1.8

• 2.5

• 3.6

• 10