The displacement $y(t) = A\,\sin \,(\omega t + \phi )$ of a pendulum for $\phi = \frac {2\pi }{3}$ is correctly represented by

If the length of simple pendulum is increased by $300\%$, then the time period will be increased by  ….. $\%$

A 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 a, the period of oscillation will

A simple pendulum with length  $L$ and mass $m$ of the bob is vibrating with an amplitude $A$. The maximum tension in the string is

A pendulum bob is swinging in a vertical plane such that its angular amplitude is less than $90^o$. At its highest point, the string is cut. Which trajectory is possible for the bob afterwards.