Exams › NEET › Physics

A force of 250 N is required to lift a 75 kg mass through a pulley system. In order to lift the mass through 3 m, the rope has to be pulled through 12 m. The efficiency of system is

1. 50%
2. 75%
3. 33%
4. 90%

Correct answer: 75%

Solution

Efficiency is calculated as (Work output / Work input) × 100. Work output is mgh = 75 × 10 × 3 = 2250 J. Work input is force × distance = 250 × 12 = 3000 J. Efficiency = (2250 / 3000) × 100 = 75%.

Related NEET Physics questions

• Assertion A load when lifted vertically up requires greater effort than to roll the same load up the ramp. Reason The work done in lifting the load vertically up is less.
• The graph between the resistive force acting on a body and the position of the body travelling in a straight line is shown in the figure. The mass of the body is \( 25 \mathrm{kg} \) and initial velocity is 2 m/s.When the distance covered by the bodyi \( s 4 \mathrm{m}, \) its kinetic energy would be
• Potential energy increases with the increase in :
• Three different objects of masses m1, m2, and m3 are allowed to fall from rest and from the same point O along three different frictionless paths. The speeds of the three objects on reaching the ground will be in the ratio of
• What is the minimum velocity with which a body of mass m must enter a vertical loop of radius R so that it can complete the loop?
• A particle of mass m₁ is moving with a velocity v₁ and another particle of mass m₂ is moving with a velocity v₂. Both of them have the same momentum but their different kinetic energies are E₁ and E₂ respectively. If m₁ > m₂ then:

⚔️ Practice NEET Physics free + battle 1v1 →