Q 11-04-114JEE MainJEE Main 2023 (25 Jan, Shift 1)Easy
A car is moving with a constant speed of $20\ \text{m s}^{-1}$ in a circular horizontal track of radius $40\ \text{m}$. A bob is suspended from the roof of the car by a massless string. The angle made by the string with the vertical will be (Take $g=10\ \text{m s}^{-2}$)
Answer: (C) $\dfrac\pi4$
$T\sin\theta=\dfrac{mv^2}{r}$, $T\cos\theta=mg$, so $\tan\theta=\dfrac{v^2}{rg}=\dfrac{400}{400}=1$ and $\theta=\dfrac\pi4$.
Solution by Sreeraj P, M.Sc Physics