Question

Anita used a single movable pulley to lift a bucket of water from a well. She lubricates the pulley. Which of the following statements is true regarding the performance of the pulley used?

विकल्प

• Mechanical Advantage decreases and efficiency increases.

• Velocity Ratio increases and efficiency decreases.

• Mechanical Advantage remains unchanged and efficiency increases.

• Velocity Ratio remains unchanged and efficiency increases.

Answer 1

Velocity Ratio remains unchanged and efficiency increases.

Explanation:

When the pulley is lubricated, the Velocity Ratio (VR) remains unchanged because VR depends only on the physical structure of the pulley system. The efficiency increases because the reduction in friction allows more of the applied effort to contribute to lifting the load, thus increasing the mechanical advantage.