An object executes circular motion with constant speed when- ever a net force of constant magnitude acts perpendicular the velocity. what happens to the speed if the force is not per- pendicular to the velocity? to "ems set. 7.2 rotational motion under constant angular acceleration 7.3 tangential velocity, tangential acceleration, and centripetal acceleration 5. a dentist's drill starts from rest. after 3.20 s of constant angu- lar acceleration, it turns at a rate of 2.51 x 10 rev/min. (a) find the drill's angular acceleration. (b) determine the angle (in radians) through which the drill rotates during this period. 6. va centrifuge in a medical laboratory rotates at an angu- lar velocity of 3600 rev/min. when switched off, it rotates through 50.0 revolutions before coming to rest. find the con- stant angular acceleration (in rad/s) of the centrifuge 7. a bicyclist starting at rest produces a constant angular accel- eration of 1.60 rad/s2 for wheels that are 38.0 cm in radius.