Work Done by a Force

IMPORTANT

Work Done by a Force: Overview

This Topic covers sub-topics such as Work, Work Done by Variable Force, Work Done by Friction, Work Done by a Constant Force, Work Done by Spring Force, Work Done by Gravity, Work Done by Pseudo Force and, Work Done by Normal Reaction

Important Questions on Work Done by a Force

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IMPORTANT

A body constrained to move in y – direction, is subjected to a force given by   F =(2 i ^ +15 j ^ +6 k ^ )N.  What is the work done by this force in moving the body through a distance of 10 m along y – axis?

EASY
IMPORTANT

A body, constrained to move in y – direction, is subjected to a force given by   F =(2 i ^ +15 j ^ +6 k ^ )N.  The work done by this force in moving the body through a distance of 10 m along y – axis is

MEDIUM
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The area of the acceleration-displacement curve of a body gives

EASY
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Find the work done by the gravity on the man of mass 60 kg while going up the escalator of height 4 m.(Take g=10 m s-2)

EASY
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Johnny and his sister Jane race up a hill. Johnny weighs twice as much as Jane and takes twice the time as long as Jane to reach the top. Compared to Jane:

MEDIUM
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A block of mass 50 kg just slides over a distance of 1 m. If the coefficient of friction between their surfaces is 0.2, the work done against friction is

HARD
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A cubical vessel of height 1 m is full of water. What is the amount of work done in pumping water out of the vessel?

[Take g=10 ms-2]

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When a force is applied on a moving body, its motion is retarded. Then the work done is

EASY
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A body of mass 3 kg is under a force, which causes a displacement in the body given by s= t33 (in meters). Find the work done by the force in the first 2 seconds.

MEDIUM
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A block of mass 50 kg just slides over a distance of 1 m. If the coefficient of friction between their surfaces is 0.2, the work done against friction is

HARD
IMPORTANT

A cubical vessel of height 1 m is full of water. What is the amount of work done in pumping water out of the vessel?

[Take g=10 ms-2]

MEDIUM
IMPORTANT

When a force is applied on a moving body, its motion is retarded. Then the work done is

MEDIUM
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Force of 4 N is applied on a body of mass 20 kg. Find the work done in Joules in 3rd second.

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A 200 kg cart is pushed slowly up the incline. The work done by the pushing force in order to move the cart up along the incline on to the platform 1.5 m above the ground is (neglecting friction, g=9.8 m/s2)

HARD
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A body, possessing kinetic energy T, moving on a rough horizontal surface, is stopped in a distance y. The frictional force exerted on the body is :-

MEDIUM
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The system of two masses 2 kg and 3 kg shown in the figure is released from rest. The work done on 3 kg block by the force of gravity during first 2 seconds of its motion is g=10 m s-2

Question Image

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The force acting on the block is 102 N with an angle 135°. Calculate the work done when the displacement is Δx=5 m

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A force F=3x2Ni^+4 Nj^, (where x is in meters), acts on a particle. Assuming that only kinetic energy is changed the net work done on the particle as it moves from position 2i^+3j^ m to 3i^+1j^ m

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Consider a drop of rainwater having mass 1 g falling from a height of 1 km. It hits the ground with a speed of 50 m s-1. Take g constant with a value 10 m s-2. The work by the
i) Gravitational force and
ii) Resistive force of air is

EASY
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Force acting on a particle moving in a straight line varies with the velocity of the particle as F=Kv. Here, K is a constant. The work done by this force in time t is