Rotational Motion Question 3
Question 3 - 25 January - Shift 1
A car is moving with a constant speed of 20 $m / s$ in a circular horizontal track of radius 40 $m$. 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 $g=10$ $m / s^{2}$ )
(1) $\frac{\pi}{6}$
(2) $\frac{\pi}{2}$
(3) $\frac{\pi}{4}$
(4) $\frac{\pi}{3}$
Show Answer
Answer: (3)
Solution:
Formula: Banking Of Road Without Friction
$T \cos \theta=mg$
$T \sin \theta=\frac{mv^{2}}{R}$
$\tan \theta=\frac{v^{2}}{Rg}$
$\tan \theta=\frac{20^{2}}{40 \times 10}$
$\tan \theta=1$
$\Rightarrow \theta=\frac{\pi}{4}$
