How much time does it take a power drill accelerating at 64.3 rad/s2 to achieve 1500. rotations per minute(rpm)?

First of all, we need to convert the final angular velocity from rpm (revolutions per minute) to rad/s. Keeping in mind that


We have


the angular acceleration is given by

where  is the initial velocity (in this case, zero), and  is the time needed to accelerate the drill to its final velocity. Using , we can calculate :

The answer is frictional force