Name:    Qluiz: Circular Motion

True/False
Indicate whether the statement is true or false.

1.

The rotational speed of a wheel is defined as the number of rotations it makes in a unit of time.

2.

When you whirl a can on the end of a string, the centripetal force on the can is actually the pull of the string on the can.

3.

When an object turns about an external axis, the motion is called rotation.

4.

Any force that causes an object to move in a circular path is called a centripetal force.

5.

A bug on a turning phonograph record will make more turns per minute if it is located toward the center of the record.

Multiple Choice
Identify the choice that best completes the statement or answers the question.

6.

If you whirl a tin can on the end of a string and the string suddenly breaks, the can will
 a. fly off, tangent to its circular path. b. fly directly toward you. c. spiral in toward your hand. d. spiral away from your hand. e. fly directly away from you.

7.

A tin can whirled on the end of a string moves in a circle because
 a. there is an inward force acting on the can. b. there is a force on the can pulling it outward. c. once the can starts moving, that is its natural tendency. d. the can continually pulls on the string. e. all of the above

8.

A car travels in a circle with constant speed. The net force on the car
 a. is directed toward the center of the curve. b. is zero because the car is not accelerating. c. is directed forward, in the direction of travel. d. none of the above

9.

What is the centripetal acceleration on the can in this diagram below if the radius of the circle was 2.0 meters, and the velocity was 5.0 m/s?
 a. 125 m/s2 c. 2.5 m/s2 b. 12.5 m/s2 d. 25 m/s2

10.

What is the net force on the 0.30 kg ball in this example if the centripetal acceleration was 50.0 m/s2?
 a. 30 N c. 150 N b. 0.006 N d. 15 N

11.

The tangential speed at the outer rim of a Ferris wheel is 20 m/s. What is the tangential speed of a position half way from the center to the outer rim?
 a. 20 m/s c. 5 m/s b. 10 m/s d. 8 m/s

12.

You sit at the outer rim of a Ferris wheel that rotates at 6 revolutions per minute (RPM). What would your rotational speed be if you were instead clinging to a position halfway from the center to the outer rim?
 a. 3 RPM c. 6 RPM b. 12 RPM d. 4 RPM

13.

A vertical pole standing against a wall topples to the ground and the center of the pole has a speed of 10 m/s as it hits. With what speed does the far end of the pole hit the ground?
 a. 20 m/s c. 100 m/s b. 10 m/s d. 5 m/s

14.

You are sitting on a merry-go-round and the outer edge 2 meters from the center and have a tangential speed of 4 m/s.  What is your centripetal acceleration (ac)?
 a. 4 m/s2 c. 2 m/s2 b. 8 m/s2 d. 6 m/s2

15.

The tangential speed at the outer rim of a Ferris wheel is 8 m/s. What is the tangential speed of a position half way from the center to the outer rim?
 a. 2 m/s c. 8 m/s b. 16 m/s d. 4 m/s

16.

You are driving in a 1000 kg car around a circular path at a constant speed of 1 m/s.  The track has a radius of 20 meters.  What is the centripetal force acting on the car?
 a. 2000 N c. 50 N b. 1000 N d. 100 N

17.

Which has greater linear speed, a horse near the outside rail of a merry-go-round or a horse near the inside rail?
 a. Neither—they both have the same linear speed. b. The outside horse c. The inside horse

18.

A ball on a rope swings around a vertical pole.  In which direction will the ball fly if released at the location shown?

 a. W c. Z b. Y d. X