A disk rotates about its central axis starting from rest and accelerates with constant angular acceleration. At one time it is rotating at 9.80 rev/s; 80.0 revolutions later, its angular speed is 18.0 rev/s. Calculate (a) the angular acceleration (rev/s2), (b) the time required to complete the 80.0 revolutions, (c) the time required to reach the 9.80 rev/s angular speed, and (d) the number of revolutions from rest until the time the disk reaches the 9.80 rev/s angular speed.

Atennis player used a tennis racket to hit a tennis ball with a mass of 0.25 kg with a force of 5.25 newtons. how does the force the tennis racket exerted on the tennis ball compare with the force the tennis ball exerted on the tennis racket? a. the force of the tennis racket on the tennis ball is equal in magnitude and opposite in direction to the force the tennis ball exerted on the tennis racket. b. the force of the tennis racket on the tennis ball is equal in magnitude and in the same direction as the force the tennis ball exerted on the tennis racket. c. the force of the tennis racket on the tennis ball is less in magnitude and in the same direction as the force the tennis ball exerted on the tennis racket. d. the force of the tennis racket on the tennis ball is greater in magnitude and opposite in direction as the force the tennis ball exerted on the tennis racket.