Subsection 3.2.5 Torque
Just as force plays a role in moving object in linear motion, torque plays the same role in rotational motion of an object about an axis. Torque in rotational motion is a linear analogue of force. Actually, torque is a turning effect of force which acts on a body in specific direction and at specific position. For example, if a force is applied at the center of mass of a body it will not produce any torque. But, if the same amount of force is acting off center then the body starts rotating about an axis. Just as force is a push or a pull, torque is a twist to an object around a specific axis. The magnitude of torque depends on the magnitude of applied force and the lever arm and is given by
\begin{equation}
\mathcal{T} = F r\tag{3.2.8}
\end{equation}
