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JEE · NEET Physics

Class 11 · Chapter 5

Work, Energy & Power

Overview, notes, short notes, formula sheet, daily practice problems, previous year questions, and videos for this chapter — all in one place.

Work, Energy & Power Practice Questions

18 questions on Work, Energy & Power. Try each one before checking the answer.

Q1.

A force F = (4î + 3ĵ) N displaces a particle by d = (2î − ĵ) m. Find the work done.

Q2.

A force of 20 N displaces a body through 10 m. If the work done is 100√3 J, find the angle between the force and the displacement.

Q3.

A force F = (2x + 3) N acts on a body along the x-axis. Find the work done as the body moves from x = 0 to x = 4 m.

Q4.

A 1000 kg car, starting from rest, speeds up to 20 m/s over a distance of 50 m on a frictionless level road under a constant driving force. Find that force.

Q5.

A spring of force constant 200 N/m is stretched by 10 cm. Find the elastic potential energy stored.

Q6.

A spring stores elastic potential energy U when stretched by x. How much energy does the same spring store when stretched by 3x?

Q7.

The potential energy of a particle is given by U(x) = 5x² − 10x (in joules). Find its equilibrium position.

Q8.

A particle's potential energy is given by U(x) = 3x² − 6x (in joules), with equilibrium at x = 1 m. What kind of equilibrium is this?

Q9.

The kinetic energy of a body increases by 21%. Find the percentage increase in its momentum.

Q10.

A 2 kg ball falls from rest through a height of 10 m, but air resistance limits its speed to 12 m/s just before landing. Find the energy lost to air resistance. (g = 10 m/s²)

Q11.

A 2 kg block moving at 6 m/s on a smooth horizontal surface collides with a spring of force constant 800 N/m. Find the maximum compression of the spring.

Q12.

A 1 kg mass is attached to a vertical spring of force constant 100 N/m and released suddenly from the spring's natural length (not lowered gently). Find the maximum extension. (g = 10 m/s²)

Q13.

A motor lifts a 50 kg mass at a constant velocity of 2 m/s. Find the power delivered. (g = 10 m/s²)

Q14.

A body starts from rest and moves under a constant power source. The distance it covers is proportional to which power of time?

Q15.

A pump raises 900 kg of water per minute to a height of 20 m. If the pump's efficiency is 60%, find the electrical input power. (g = 10 m/s²)

Q16.

A 4 kg block slides on a rough horizontal floor (μ = 0.2) with an initial speed of 10 m/s. Find the distance it travels before stopping. (g = 10 m/s²)

Q17.

Which of the following is NOT a conservative force?

Q18.

A force F = (5 − 2x) N acts on a particle along the x-axis. Find the work done as it moves from x = 0 to x = 3 m.

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