What is the length of a simple pendulum,which ticks seconds (in $m$)?

The period of a simple pendulum is doubled,when

The bob of a pendulum of length $l$ is pulled aside from its equilibrium position through an angle $\theta$ and then released. The bob will then pass through its equilibrium position with speed $v$,where $v$ equals

The bob of a simple pendulum of length $L$ has a mass $m$ and charge $q$. The pendulum is suspended between the plates of a charged parallel plate capacitor. The direction of the electric field is shown in the figure. The period of oscillations of the simple pendulum is (acceleration due to gravity $g > qE/m$):

$A$ person of mass $M$ is sitting on a swing of length $L$ and swinging with an angular amplitude $\theta_0$. If the person stands up when the swing passes through its lowest point,the work done by him,assuming that his centre of mass moves by a distance $l$ $(l << L)$,is close to

The time period of a simple pendulum on a freely moving artificial satellite is