Question

A car is moving in a circular horizontal track of radius $10\,m$ with a constant speed of $10\, m/s$. A plumb bob is suspended from the roof of the car by a light rigid rod. The angle made by the rod with the vertical is $(Take \,g \,=\, 10 m/s^2)$

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

Answer 1

Answer: (C)

$45^\circ$

Answer 2

FBD of bob is T sin $\theta=\frac{mv^2}{R}$
and T cos $\theta$ = mg
$\therefore \tan\theta=\\\frac{v^2}{Rg}=\frac{(10)^2}{(10)(10)}$
tan $\theta=1$
or $\ \ \ \ \ \ \theta=45^\circ$