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Physics · PYQ NEET UG 2018
हिन्दीA solid sphere is in rolling motion. In rolling motion, a body possesses translational kinetic energy (\( K_t \)) as well as rotational kinetic energy (\( K_r \)) simultaneously. The ratio \( K_t : (K_t + K_r) \) for the sphere is
Correct answer · Option 2
\( 5 : 7 \)
Explanation
For a solid sphere, \( K_t = \frac{1}{2} mv^2 \) and \( K_r = \frac{1}{2} I \omega^2 = \frac{1}{2} (\frac{2}{5} m R^2) (\frac{v}{R})^2 = \frac{1}{5} mv^2 \). Total energy \( K_t + K_r = \frac{1}{2} mv^2 + \frac{1}{5} mv^2 = \frac{7}{10} mv^2 \). Thus the ratio is \( \frac{1/2}{7/10} = 5 : 7 \).
