Question:
A simple pendulum is suspended from the ceiling of a car taking a turn of radius $10 \mathrm{~m}$ at a speed of $36 \mathrm{~km} / \mathrm{h}$. Find the angle made by the string of the pendulum with the vertical if this angle does not change during the turn. Take $g=10 \mathrm{~m} / \mathrm{s}^{2}$.
Solution:
$\mathrm{T} \sin \theta=\frac{m v^{2}}{R}$
$T \cos \theta=m g$
$\tan \theta=\frac{v 2}{R g}$
$\tan \theta=\frac{\left(36 \times \frac{5}{38}\right)^{2}}{10 \times 10}$
$\theta=45^{\circ}$