Angular speed, w, is the rate at which an object rotates. Although usually measured in radians per second, w can also be expressed in degrees per second. For instance, consider a merry-go-round. Figure 1 shows its angular speed as a function of time, t. In this graph, a positive value of w indicates counterclockwise rotation.
FIGURE 1
A "complete revolution" occurs when the merry-go-round turns through one full circle.

1. | Between t = 0 s and t = 10 s, about how many revolutions does the merry-go-round complete?

A. | 1

B. | 2

C. | 3

D. | 4

2. | Between t = 10 s and t = 20 s, the merry-go-round:

A. | rotates clockwise, at a constant rate.

B. | rotates clockwise, and slows down.

C. | rotates counterclockwise, at a constant rate.

D. | rotates counterclockwise, and slows down.

3. | Between t = 30 s and t = 40 s, the merry-go-round:

A. | rotates clockwise, at a constant rate.

B. | rotates clockwise, and slows down.

C. | rotates counterclockwise, at a constant rate.

D. | rotates counterclockwise, and slows down.

4. | Consider two children riding on the merry-go-round. Child 1 sits near the edge, as shown in figure 2. Child 2 sits closer to the center. FIGURE 2 Top view of merry-go-round Let v1 and v2 denote the linear speed of child 1 and child 2, respectively. Which of the following is true?

A. | v1 > v2

B. | v1 = v2

C. | v1 < v2

D. | We cannot determine which is true, without more information.

5. | The scalar angular acceleration is the rate of change of the angular speed with time. Which graph best represents the merry-go-round's scalar angular acceleration between t = 0 s and t = 20 s?

A. | A

B. | B

C. | C

D. | D

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