Q 11-04-118JEE MainJEE Main 2023 (11 Apr, Shift 1)Easy
A coin placed on a rotating table just slips when it is placed at a distance of $1\ \text{cm}$ from the centre. If the angular velocity of the table is halved, it will just slip when placed at a distance of ______ from the centre.
Answer: (B) $4\ \text{cm}$
Slipping starts when $m\omega^2r=\mu mg$, so $r\propto\dfrac1{\omega^2}$. Halving $\omega$ gives $r=4\ \text{cm}$.
Solution by Sreeraj P, M.Sc Physics