Question #120978

A thin rod of lengh L lies on the +x-axis with its left end at the origin. A string pulls on the rod with a force f directed toward P point a distance is above the rod should you attach the string to det the greatest torque about the origin if point P is above the right end of the rod.

Expert's answer

**Explanations & Calculations**

- Assume the force being applied is located as shown in the picture.
- Tension in the string is equal to the magnitude of the applied force.

- Torque around a pivotal point is defined as the force "\\times" perpendicular distance to it from the pivot. "\\tau = f \\times d"

- Therefore, torque due to the applied force f can be written as "f\\cos\\theta \\times l"
- Now, maximize the product, "\\cos\\theta" should be maximum. "-1 \\eqslantless \\cos\\theta \\eqslantless1"
- "\\cos\\theta_{maximum} = 1"

- Therefore, "\\tau_{max} = f \\times l"

- Maximum torque is obtained when the force is applied on the far end from the pivotal & perpendicular to the rod.

Learn more about our help with Assignments: MechanicsRelativity

## Comments

## Leave a comment