Question

A disc is rolling without slipping on a straight surface. The ratio of its translational kinetic energy to its total kinetic energy is

• A. $\frac{2}{3}$
• B. $\frac{1}{3}$
• C. $\frac{2}{5}$
• D. $\frac{3}{5}$

Answer 1

The correct option is A $\frac{2}{3}$

$TKE=\frac{1}{2}m{v}^2$
$RKE=\frac{1}{2}I{\omega }^2$
$\omega =v/R$
$\Rightarrow \frac{TKE}{TKE+RKE}=\frac{2}{3}$