If the particle rotating in xy plane about the origin under the effect of force and at any instant the position vector of the particle is , then
τ = rF sin φ
[whereφis the angle between the direction of and ]
(1) Maximum and minimum torque:
As or τ = rF sin φ
(2) If a body is acted upon by more than one force, the total torque is the vector sum of torques due to each force.
(3) A body is said to be in rotational equilibrium if resultant torque acting on it is zero i.e.
(4) Rotatory Motion :