If a stone of mass 0.5 kg tied to one end of a wire is whirled in a circular path of radius 2 m with a speed $40 \mathrm{rev} / \mathrm{min}$ in a horizontal plane, then the tension in the wire is nearly

A wire of length 2.5 m is fixed at one end and a box of mass 4 kg is tied at the other end. If the wire rotates in a horizontal circle about the fixed end with $\frac{2}{\pi}$ rotations per second, then the tension in the wire is

If a particle of mass ' $m$ ' covers half of the horizontal circle with constant speed ' $v$ ', then the change in its kinetic energy is

Ratio of angular velocity of hour hand of a watch and the angular velocity of rotation of Earth is