7) 8) A boy has a toy ball attached to a 0.5 m string and he swings the ball in a horizontal circle with radius 0.5 m. The ball starts at rest at time t = 0 and the boy gives it a constant tangential acceleration while swinging it. If the tangential acceleration of the ball is a constant 4 III/$2, how long will it take for the ball to complete its rst four rotations? A) 1.3 s B) 4.4 s C) 3.8 s D) 6.3 s If the tangential acceleration of the ball is a constant 4 111/52, what is the centripetal acceleration of the ball at the instant it completes its fourth rotation? A) 26 In/s2 B) 67 m/s2 C) 178 m/s2 D) 79 m/s2 E) 1.8 s F) 3.1 s G) 2.5 s H) 5.0 s E) 50 m/s2 F) 202 m/s2 G) 20 m/s2 H) 44 m/s2