Circular Motion

Oct 15, 2019, 16:45 IST

About Circular Motion

When a particle moves in a circular path, it changes its direction at every moment. Speed of the particle may change or remain constant. If the particle is moving along circular path and the speed of the particle remains constant, it is called uniform circular motion.

Motion in a Circular Path

Bodies moving in a circular path are said to be in circular motion. In everyday life, in astronomy, in atomic physics etc., we have a number of examples of objects moving in almost nearly circular paths. Rotation of rigid body about an axis, rotation of automobile wheels, the spinning of earth about it axis, motion of planets round the sun, motion of electron round the nucleus of an atom etc., are examples of circular motion.

Type of Circular Motion 

There are two types of circular motion (i) Uniform Circular Motion and (ii) Non-uniform circular motion. In uniform circular motion the particle in circular path moves with a uniform speed. The particle covers equal distances in equal intervals of time. But in non-uniform circular motion, the speed of the particle in circular motion is different at different points along the circular path.

Newton’s second law tells us that when a particle accelerates there must be a net force acting on the particle in the direction of its acceleration.

Following this law, as the particle in uniform circular motion accelerates radially inwards ( centripetal ). Hence, we call this centripetal force.

Centripetal force is not a special force. It can be any field force such as gravitational, electrostatics, magnetic, and others.

This can be also be any constant force ( reaction force ) i.e. friction and normal reaction, etc.

When we are sitting by the side of a window of a car while it negotiates a curve, we feel as if we are pushed away from the center of the curve. This is what we call centrifugal forces as it gives a physical sensation of b