# physics

posted by
**kristy**
.

A disk rotates about its central axis starting from rest and accelerates with constant angular acceleration. At one time it is rotating at 7.8 rad/s; 60 radians later, its angular speed is 19 rad/s. Calculate (a) the angular acceleration (rad/s2), (b) the time required to complete the 60 radians, (c) the time required to reach the 7.8 rad/s angular speed, and (d) the number of radians from rest until the time the disk reaches the 7.8 rad/s angular speed.