Question

under what condition is the torque zero?

Answer 1

Where F is the force, r is the distance between the axis of rotation and the point where the force happens, and θθ is the angle between the direction of the force and the line that joins the axis to the point. If any of these is zero, the force is zero.And, of course, if there are many torques and they cancel each other out, the total torque is also zero

Answer 2

Here is your answer.

In Rorational equilibrium,the value of torque is Zero.

Hope that this helps you.