Exams › NEET › Physics

A particle of mass m is driven by a machine that delivers a constant power of k watts. If the particle starts from rest the force on the particle at time t is

1. √mk t⁻¹/²
2. √2mk t⁻¹/²
3. √m/k t⁻¹/²
4. mk t⁻¹/²

Correct answer: √2mk t⁻¹/²

Solution

The power delivered is constant, so P = Fv. Since the particle starts from rest, its velocity increases with time. Using the relation P = Fv and v = (2Pt/m)^(1/2), we find F = P/v = √(2mk)/t^(1/2). Thus, the correct option is B.

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 →