The spring constant of a spring depends on its

A spring of spring constant k is cut into two equal halves. The spring constant of each half is now

Which of the following is a non-contact force ?

A girl is swinging on a swing in sitting position. When the girl stands up, the period of the swing will :

A rod is balanced vertically on one of its ends. Which one among the following is the correct nature of its state of equilibrium?

When a stone tied to a string is whirled in a circle, the work done on it by the string: