Question

A car is moving on a circular horizontal track of radius $10m$ with a constant speed of $10$ $m{s}^{-1}$. A plumb bob is suspended from the roof of the car by a light rigid rod of length $1.00m$.The angle made by the rod with the track is

• A. $zero$
• B. ${30}^{\circ }$
• C. ${45}^{\circ }$
• D. ${60}^{\circ }$

Answer 1

Answer: (C)

${45}^{\circ }$

$\frac{m{v}^2}{R}=T\sin \theta$ and $mg=T\cos \theta$
$\therefore \frac{v^2}{Rg}=\tan \theta$
Thus $\tan \theta =\frac{{10}^2}{10\times 10}=1$ or $\theta ={45}^{\circ }$