Center of mass(C.M)

 A point with reference to a body at which the entire mass of the body is meant to be concentrated, is called its centre of mass. The applied force on centre of mass of a body produces linear acceleration but not rotation.

In translational motion, when a force is applied, each point on a rigid body experiences the equal linear displacements in order that the motion of the entire body are often represented by one particle. But, just in case of rotational motion, the various points of a body have different linear displacements. These all points of the body rotate with an equivalent angular velocity except one point on the body which doesn't rotate and possesses linear motion only. now is named the centre of mass of the body.