What is the angular velocity of the second hand of a clock?

$A$ particle is moving along a circular path with constant speed and centripetal acceleration '$a$'. If the speed is doubled,the ratio of its acceleration after and before the change is:

In uniform circular motion, which of the following statements is wrong?

If the direction of motion of an object performing uniform circular motion is reversed,what will be the effect on the direction of the centripetal force?

$A$ motorcyclist going around a circular track at a constant speed has:

When a particle moves in a uniform circular motion,it has: