Question

Two equal forces are applied perpendicular to a door. The first force is applied at the midpoint of the door; the second force is applied at the doorknob. Which force exerts the greater torque?

Answer 1

Answer:

The second force at the doorknob

Explanation:

The magnitude of the torque is given by the following formula:

$\tau=rFsin\theta$

F is the applied force, r is the distance of the line of action of force from the axis of rotation and $\theta$ is the angle between them, in this case is $90^\circ$ for both points.

The door's midpoint it's half the distance from the doorknob. Thus, the torque at the doorknob is twice the torque at the door's midpoint.