The figure represent two cases. In first case a block of mass `M` is attached to a string which is tightly wound on a disc of mass `M` and radius `R`. In second case `F=Mg` initially the disc is stationary in each case. if the same length of string is unwound from the disc, then

Options

A. same amount of work is done on both discs
B. angular velocities of both the discs are equal
C. both the discs have unequal angular accelerations
D. All of the above

Explanation

In first case `TltMg`
In second case `T=Mg`
torque are different, so angular acceleration are different.