# Uniform Circular Motion

When the velocity of an object changes, it is said to be in an accelerated motion. The change in velocity could be due to a change in its magnitude or direction of motion or both. Can you give an example of an object that does not change its magnitude but only direction of motion? The motion of an object along a circular path is one. When the object moves with uniform speed (constant speed), it is said to have uniform circular motion. During circular motion, the direction of the motion at any point is given by the tangent to the circle at that point. The direction of motion is therefore continuously changing. So, even though it is travelling at constant speed, its velocity is not constant. This changing velocity gives rise to an accelerated motion. Therefore the motion of an object in a circular path with a constant

speed is an accelerated motion.

Suppose the object takes t seconds to go once around the circular path of radius r, its velocity will be given by v = 2 x p x r / t or 2 x 3.14 x r / t. When an object moves along a circular path with uniform speed, its motion is called uniform circular motion.