Question

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

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

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

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

7. In what type of collision is kinetic energy conserved?

	A.	Inelastic.
	B.	Elastic.
	C.	Kinetic energy is always conserved.
	D.	Perfectly inelastic.

8. Ignoring air resistance, an object falls and gains 60 J of kinetic energy. How much gravitational potential energy did the object lose?

	A.	Exactly 60 J
	B.	More than 60 J.
	C.	Less than 60 J.
	D.	Can not be determined.

9. When is the momentum of a system not conserved?

	A.	Always.
	B.	When there are no external forces.
	C.	When there are external forces.
	D.	Never.

10. What are the conditions for an object to be in static equilibrium?

	A.	Net force and net torque are both not zero.
	B.	Net force is zero but net torque is not zero.
	C.	Net torque and net force are zero.
	D.	Net force is not zero but net torque is zero.

Please answer all of them. Thank you so much!

Answer 1