Q 11-04-132JEE MainJEE Main 2022 (24 Jun, Shift 2)Easy
A stone of mass $m$, tied to a string, is being whirled in a vertical circle with a uniform speed. The tension in the string is
Answer: (C) minimum at the highest position of the circular path.
With $\theta$ measured from the highest point, the radial equation gives
$$T + mg\cos\theta = \frac{mv^2}{r}\ \Rightarrow\ T = \frac{mv^2}{r} - mg\cos\theta$$
With $v$ constant, $T$ is least when $\cos\theta = 1$, i.e. at the highest point.
Solution by Sreeraj P, M.Sc Physics