A grindstone increases in angular speed from 4.00 rad/s to 12.00 rad/s in 3.00 s. (a) How many revolution does it turn during that time interval if the angular acceleration is constant? (b) What is the magnitude of its angular acceleration? Only use this formula/s:

Definition Definition Rate of change of angular velocity. Angular acceleration indicates how fast the angular velocity changes over time. It is a vector quantity and has both magnitude and direction. Magnitude is represented by the length of the vector and direction is represented by the right-hand thumb rule. An angular acceleration vector will be always perpendicular to the plane of rotation. Angular acceleration is generally denoted by the Greek letter α and its SI unit is rad/s 2 .