$A$ girl is swinging on a swing in the sitting position. What will be the effect on the time period of the swing if she stands up?

$A$ tunnel has been dug through the centre of the Earth and a ball is released in it. It will reach the other end of the tunnel after:

Two simple pendulums are given: the first has a bob of mass $M_1$ and length $L_1$,and the second has a bob of mass $M_2$ and length $L_2$. Given $M_1 = M_2$ and $L_1 = 2L_2$. If the vibrational energy of both is the same,which of the following statements is correct?

$A$ man measures the period of a simple pendulum inside a stationary lift and finds it to be $T$ seconds. If the lift accelerates upwards with an acceleration of $\frac{g}{4}$,then the period of the pendulum will be

$A$ simple pendulum of length $l$ has a brass bob attached at its lower end. Its period is $T$. $A$ steel bob of the same size,having density $x$ times that of brass,replaces the brass bob. Its length is then changed such that the period becomes $2T$. What is the new length?

The length of the simple pendulum is made $3$ times the original length. If $T$ is its original time period,then the new time period will be: