Final answer:
The simplest equations for torque result when calculating torques about the point where an unknown force acts, as torques by unknown forces are zero at that pivot point.
Step-by-step explanation:
When calculating torques, it is often advantageous to choose the point where an unknown force acts to simplify the calculation. The simplest equations for torque result if you take torques about the point where an unknown force acts. This is because the torque exerted by a force is zero if the force is applied at the pivot (the point chosen for calculating torques), as at the pivot lever arm (r) is zero, or if the force acts along a line through the pivot point (θ is zero).
It is important to choose a convenient pivot point to simplify the solution because any pivot point can be chosen, but the most useful ones cause torques by unknown forces to be zero. The magnitude of a torque about a fixed axis is calculated using the relation |τ| = r₁ F, where r₁ is the perpendicular distance from the axis to the line of action of the force. Selecting the point where the unknown force acts as the pivot can immensely simplify the problem-solving process.