Question

A body of mass $m$ and radius $R$ is rotating with angular velocity $\omega$ as shown in figure and kept on a surface that has sufficient friction. Then, the body will move:

• A. initially in backward direction, then along forward direction
• B. initially in forward direction, then along backward direction
• C. will always move along forward direction.
• D. none of these

Answer 1

The correct option is C will always move along forward direction.

$\omega$ is in clockwise direction, hence kinetic friction $\left(f_k\right)$ will act along forward direction to prevent slipping, by opposing rotational motion.


Hence, velocity $V$ of body will start increasing and $\omega$ starts decreasing
$\therefore V=\omega R$ condition will be achieved after some time ${}^{\prime }{t}^{\prime }$, thereafter slipping will cease and pure rolling is maintained.
Once pure rolling is established, $f_k$ will disappear and body will continue to move along forward direction with constant velocity.
$\therefore$ Option $C$ is correct.