Question

1. For an object moving in uniform circular motion, does the centripetal force do work on the object?

	A.	Yes, because work is force times distance and the object is moving from the force.
	B.	No, because the force is always perpendicular to the object's displacement.
	C.	No, because the displacement of the object is zero.
	D.	Yes, because the object is moving.

2. An object is moving along a straight line with a speed of v when it hits and sticks to an identical object that is initially at rest. After the collision, the final kinetic energy is:

	A.	Equal to the initial kinetic energy.
	B.	One fifth of the initial kinetic energy.
	C.	One fourth of the initial kinetic energy.
	D.	One half of the initial kinetic energy.

3. How can two collisions have the same change in momentum even though one collision took longer to happen than the other?

	A.	The collision that took less time had a larger average force.
	B.	The average forces were equal.
	C.	The change in momentum can never be equal.
	D.	The collision that took less time had a lower average force.

4. You throw a ball with an initial momentum +p. What is the change in momentum if the ball hits a wall and rebounds elastically in the opposite direction?

	A.	-2p
	B.	p
	C.	0
	D.	-p

Answer 1