PHYS 231 Quiz #4

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 Cheat Sheet:
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		If an equation you need is not listed here, ask.

Multiple choice: 1 pt. each

1. A gangster on television shoots a pistol and barely flinches. The bullet hits the victim, sending him flying through a picture window. This unrealistic scene violates

A. Newton's second law.

B. energy conservation.

* C. momentum conservation.

D. nothing. Sounds like a plausible situation to me.

2. The Human Cannonball is shot out of a cannon. In midair, he realizes that the net is not positioned correctly. He whips off his helmet and throws it away from the cannon. This makes him land

A. farther away than he would with the helmet on.

* B. closer than he would with the helmet on.

C. in the same spot as if he had the helmet on.

D. back at the cannon.

3. The wheels of a cart are rolling at 10 rotations per second. The cart is moving at a linear velocity of

A. 1.59 m/s.

B. 10 m/s.

C. 62.8 m/s.

* D. We need more information to answer this.

4. The moment of inertia of an object does NOT depend on

* A. the angular velocity of the object.

B. the mass of the object.

C. the geometry of the object.

D. the axis of rotation.

5. If the net torque on an object is zero, then what do we know to be true?

A. The linear acceleration of the object is zero.

* B. The angular acceleration of the object is zero.

C. The linear velocity of the object is zero.

D. The angular velocity of the object is zero.

6. A diver takes a dive and in midair pulls in all his limbs, causing him to do a double somersault. This demonstrates

A. Newton's second law as applied to rotational motion.

B. the conservation of kinetic energy.

* C. the conservation of angular momentum.

D. all of the above.

7. A hoop, disk, and sphere all roll down an incline. They all have the same mass and same radius. Which one arrives last?

* A. The hoop.

B. The disk.

C. The sphere.

D. They all arrive at the same time.

8. If a planet had eight times the volume of the Earth, what would its mass have to be in order for the acceleration due to gravity on the surface to be the same as that on Earth?

A.

B.

C.

* D.

9. A force of 10 N is applied tangentially to a disk that is rotating about a fixed axis through the center. If mass of the disk is 2 kg and the resulting angular acceleration of the disk is 5 rad/s , then what is the radius of the disk? What is the torque exerted on the disk?