question_answer

A simple pendulum suspended from the ceiling of a train has a period T when the train is at rest. When the train is accelerating with a uniform acceleration the time period of simple pendulum will:

A)  decrease                           

B)  increase

C)  remain unchanged        

D)  become infinite

Correct Answer: A

Solution :

                The periodic time of a simple pendulum of length I is given by                 \[T=2\pi \sqrt{\frac{l}{g}}\] In accelerated frame, pseudo force of magnitude\[-ma\]also acts, hence net acceleration increases. Since,      \[T\propto \frac{1}{acceleration}\] \[\therefore \]Time period decreases.