Question

A ring and a disc of same mass roll without slipping along a horizontal surface with same velocity. If the $K.E$ of ring is $8J$, then the of disc is:

• A. $2J$
• B. $4J$
• C. $6J$
• D. $16J$

Answer 1

The correct option is C $6J$

Consider,

$E_{ring}=M{v}^2=8J$

$E_{disc}=\frac{3}{4}M{v}^2$

$\begin{array}{c}=\frac{3}{4}\times 8\\ =6J\end{array}$

Hence, The Option $C$ is the correct answer.