A velocity vs. time graph for an object is shown. Which parts of the graph represents the object
moving at a constant, positive acceleration?
Velocity vs Time
O W and X
25
O X and Y
20
Y
O Y and Z
15
O W and Z
Velocity (m/s)
10
Z
w
5
0
0
1
2
4
5
3
Time (s)

An athlete swings a ball, connected to the end of a chain, in a horizontal circle. the athlete is able to rotate the ball at the rate of 8.13 rev/s when the length of the chain is 0.600 m. when he increases the length to 0.900 m, he is able to rotate the ball only 6.04 rev/s. (a) which rate of rotation gives the greater speed for the ball? 6.04 rev/s 8.13 rev/s (b) what is the centripetal acceleration of the ball at 8.13 rev/s? m/s2 (c) what is the centripetal acceleration at 6.04 rev/s? m/s2