A circular disc of radius 2 m is revolving at 240 revolutions per minute. A torque is applied which slows it at constant rate of (pie) radian/sec 2. In what time the disc will completely stop. Ans. 8 sec.

Asked by  | 15th Oct, 2013, 10:47: PM

Expert Answer:

We have the kinematic equation v = u + at,  for circular motion as;
 
? = ?0 + ?t
 
Here, the torque is acting to stop the disc. Hence, angular acceleration is negative, that is, ? = -? rad/s2.
 
Thus, we have
 

Answered by Romal Bhansali | 17th Oct, 2013, 10:37: AM

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