Question

A disc of mass 2 kg and radius 0.2 m is rotating with angular velocity 30 rads^-1 . What is angular velocity, if a mass of 0.25 kg is put on periphery of the disc?

(a) 24 rad s^-1 

(b) 36 rad s^-1 

(c) 15 rad s^-1 

(d) 26 rad s^-1

Answer 1

Correct option (a) 24 rad s^-1   

Explanation:

According to law of conservation of angular momentum, 

Angular momentum is conserved until external torque is not applied