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Question:

A solid sphere is in rolling motion. In rolling motion, a body possesses translational kinetic energy (Kt) as well as rotational kinetic energy (Kr) simultaneously. The ratio Kt:(Kt+Kr) for the sphere is?

7:10

2:5

5:7

10:7

Solution:

The correct option is D
5:7
Kt=1/2mv²
Kr=1/2IW²=1/2 × (2/5 × mr²) × (v²/r²) = 1/5mv²
→ Kt/(Kt+Kr) = (1/2mv²)/((1/2+1/5)mv²) = 1/(7/10) = 5/7
Option 4.