Question

If a force is applied at the hinge of a door instead of the handle, then

• A. The door will rotate more easily.
• B. The door will rotate with more difficulty.
• C. The door will rotate if only the force is greater than a minimum value.
• D. The door will not rotate at all.

Answer 1

The correct option is D

The door will not rotate at all.

The moment of a force is given by the product of the force and its perpendicular distance. As the force is being applied at the hinge, its perpendicular distance from the hinge will be zero and hence its moment about the hinge will be zero. Hence, it won’t cause the door to rotate.