Q67 / 75 · JEE Main 2025 (24 Jan Shift 2) · Physics
A solid sphere is rolling without slipping on a horizontal plane. The ratio of the linear kinetic energy of the centre of mass of the sphere and rotational kinetic energy is :
- A$\frac{3}{4}$
- B$\frac{4}{3}$
- Correct answerC$\frac{5}{2}$
- D$\frac{2}{5}$
Solution
$\begin{aligned}
& \mathrm{KE}_{(T)}=\frac{1}{2} m v^2 \\
& \mathrm{KE}_{(R)}=\frac{1}{2} \cdot \frac{2}{5} m R^2 \cdot \frac{v^2}{R^2}=\frac{1}{2} m v^2\left(\frac{2}{5}\right)
\end{aligned}$
So, $\frac{\mathrm{KE}_{(T)}}{\mathrm{KE}_{(R)}}=\frac{5}{2}$
Hence, the correct answer is option: 'C'.