Question

A simple pendulum of length $l$ has been set up inside a railway wagon sliding down a frictionless inclined plane having an angle of inclination $\theta ={30}^{\circ }$ with the horizontal. The period of oscillation as recorded by an observer inside the wagon is

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

On the inclined plane, the effective acceleration due to gravity,

$g^{\prime }=gcos30=g\times \frac{\sqrt{3}}{2}$

$\therefore T=2\pi \sqrt{\frac{l}{g^{\prime }}}=2\pi \sqrt{\frac{2l}{\sqrt{3}g}}$