Question

If the radius of earth shrinks by 0.2% without change in its mass, the % change in its angular velocity is

• A. increases by 0.4%
• B. increases by 0.1 %
• C. decreases by 0.4%
• D. increases by 0.2 %

Answer 1

Answer: (A)

increases by 0.4%

Answer 2

$I_{\omega} = \frac{2}{5} MR^2 \omega$ = Constant $\omega \, \propto \, R^{-2}$ and $\frac{\Delta \omega}{\omega} = -2 \frac{\Delta R}{R}$