Question

A cord is wound round the circumference of wheel of radius 'r'. The axis of the wheel is horizontal and moment of inertia about it is 'I'. A weight 'mg' is attached to the end of the cord and falls from rest. After falling through a distance h, the angular velocity of the wheel will be

• A.
• B.
• C.
• D.

Answer 1

Answer: (B)

According to law of conservation of energy $mgh=\frac{1}{2}(I+m{r}^2){\omega }^2\Rightarrow \omega =\sqrt{\frac{2mgh}{I+m{r}^2}}.$