Question

A simple pendulum of length L has been set up inside a railway wagon sliding down a frictionless inclined plane of inclination $\theta$ with the horizontal.What will be its period of oscillation as recorded by an observer inside the wagon

• A. $2\pi \sqrt{\frac{L}{gcos\theta }}$
• B. $2\pi \sqrt{\frac{L}{g}}$
• C. $2\pi \sqrt{\frac{L}{gsin\theta }}$
• D. $2\pi \sqrt{\frac{Lcos\theta }{g}}$

Answer 1

The correct option is A $2\pi \sqrt{\frac{L}{gcos\theta }}$

when sliding an inclination $g_{eff}=gcos\theta$
Time period $T=2\pi \sqrt{\frac{L}{g_{eff}}}$
$=2\pi \sqrt{\frac{L}{gcos\theta }}$