Question

A thin circular ring of mass m and radius ft is rotating about its axis with a constant angular velocity ω.Two objects each of mass M are attached gently to the opposite ends of a diameter of the ring. The ring now rotates with an angular velocity  ω =

(a) ω(m + 2M)/m

(b) ω(m - 2M)/(m + 2 M)

(c) ωm/(m +M)

(d) ωm/(m +2 M)

Answer 1

Correct Option (d) ωm/(m +2 M)

Explanation: 

As no external torque is acting on the system, angular momentum of system remains conserved.

SO, by conservation of angular momentum, i.e.,