A uniform disc of mass m and radius r and a point mass m are arranged as shown in the figure. The acceleration of point mass is: (Assume there is no slipping between pulley and thread and the disc can rotate smoothly about a fixed horizontal axis passing through its centre and perpendicular to its plane)
(A) g / 2
(B) g / 3
(C) 2g / 3
(D) none of these
Correct option: (C) 2g / 3
Explanation:
Let a & α be linear
and angular acceleration of disc respectively
a = rα.........(i)
Torque about centre of disc
From eqn. (i) & (ii)
mgr = 3 / 2 mr2 (a/r)
