Chapter 9, Problem 63A

To determine

To rank:The torques on the five doors from least to greatest.

Explanation of Solution

Given:

The given doors are shown below.

Also, same force is applied on each door.

Torque depends on the magnitude of applied force,distance from the point where force is applied to the axis of rotation and the angle made by force with the axis of rotation.

For door E, the force applied is parallel so torque is zero.

For door D, the force applied near the axis of the door so the torque is zero.

For door C, the force applied at middle of the door making some angle with the door.

For door B, the force applied perpendicular and at center of the door.

For door A, the force applied at other end of the door, so torque will be high. That is greatest torque produced when force is applied away from the door hinge and at an angle perpendicular to the door.

So, ranking from least to greatest of door is E=D, C, B and A.