Question

A uniform disk of mass $50$ $kg$ is rolling without slipping with a speed of $0.4 \;m/s$. Find minimum energy required to bring the disk to rest (in $J$).

Answer 1

The Correct Answer is : $6$ $J$
$KE=\frac{1}{2}mv^2_{ω}+\frac{1}{2}(\frac{mr^2}{2})ω^2$
$K=\frac{3}{4}mv^2$
$=\frac{3}{4}\times50\times(4)\times(0.4)$
$=6 \ \text{J}$