Question

A boy is swinging in a swing. If he stands the time period will
A. First decreases, then increase
B. Decrease
C. Increase
D. Remain same

Answer 1

Hint:Here we have to consider the effective length of a simple pendulum.
A basic pendulum's effective length is the distance between the suspension points and the centre of the bob. The longer the string length, the longer the pendulum falls; and thus the longer the pendulum duration, or the back and forth swing. The farther the pendulum goes, the greater the amplitude or angle; and hence, the longer the period.)

Complete answer:
The time period for effective length in a simple pendulum is given by:
$T = 2\pi \sqrt {\dfrac{l}{g}} $
Where $l$ is the length of the pendulum and $g$ is the acceleration due to gravity.

From the formula as we can see the acceleration due to gravity decreases with increase in time period, the stronger the gravitational pull, the shorter is the period of oscillations of a pendulum.The effective length of the swing reduces when a boy seated on a swing stands up on the swing. The time period therefore reduces as the length decreases. As the oscillation frequency is inversely proportional to the time period, in the present case of a boy standing up on the swing, it rises.

Hence, we can see that option B is correct.

Additional information:
A pendulum's length (swing) is independent of the mass of the pendulum. It relies on the length of the pendulum instead. This will mean that objects fell regardless of mass at a rate.
Its length and acceleration due to gravity are the only factors that influence the life of a single pendulum. The period is entirely independent from other variables, such as mass.

Note:The time period of a swing may also vary depending on the length of the individual sitting or standing on the swing. Since, the time period is directly proportional to the square root of length of the swing, so if the length increases the time period may increase and vice versa.