Concentric and eccentric forces :
Concentric force can be described as force that is applied along an imaginary line that passes through an object's centre of gravity. A concentric force will result in the object travelling along a direct path in the direction of applied force. This is known as translation : where all parts of an object in motion are moving with the same velocity and in the same direction.
When force is not applied along the line of centre of gravity, the object will turn. Force that is not applied along the line of centre of gravity is known as eccentric force. Eccentric forces produce rotation.