Question

A square threaded screw is used to lift a load \( W \) by applying a force \( F \). Efficiency of square threaded screw is expressed as

• A. The ratio of work done by \( W \) per revolution to work done by \( F \) per revolution
• B. \( \frac{W}{F} \)
• C. \( \frac{F}{W} \)
• D. The ratio of work done by \( F \) per revolution to work done by \( W \) per revolution

Hint:

The efficiency of mechanical devices like screws can often be defined as the ratio of work done by the load to the work done by the applied force. Always check the given definitions carefully.

Answer 1

The Correct Option is A

The efficiency \( \eta \) of a square threaded screw is defined as the ratio of the work done by the load (\( W \)) to the work done by the applied force (\( F \)) for each revolution. This is expressed as: \[ \eta = \frac{\text{Work done by } W}{\text{Work done by } F} \] Thus, the correct expression for efficiency is: \[ \eta = \frac{W}{F}. \] Therefore, the correct answer is (A).