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Every year there are questions asked from this topic. You can also download Work, Energy and Power notes in the PDF format through the link shared at the end of this article.

Work- The work done by a constant force is defined as the scalar product of force and the magnitude of displacement under the influence of force. Let us assume that a variable force act on a particle, the variation of the force and the displacement due to the influence of force is shown below. Energy — Energy is a physical quantity which enables a system to do work.

There are many forms of energy in the universe but in case of mechanical energy have two forms. Kinetic Energy- The kinetic energy of a body is the energy possessed by the body by virtue of its motion.

Kinetic energy, , where v is the velocity of the body. Potential Energy- The potential energy of a body is the energy possessed by the body by virtue of its position relative to other.

## CBSE Class 11 Physics Work-Energy And Power Notes

Potential energy, , where h is the height of the of the position possessed by the body relative to the ground. It states that the change in the kinetic energy of a particle is equal to the work done on it by the net force. Where K f is the final kinetic energy and K i is the initial kinetic energy. Let us assume the variable force works from position x i to x f then according to the work-energy theorem the change in the kinetic energy is equals to the work done on by the variable force. Power- The power is defined as the work done over a time period or rate of work done is known as the power.

Potential Energy of a Spring - Let a block is attached with a spring, Initially the spring its natural relaxed condition if we compressed the spring by a constant force F. Then the work done by the force is stored in the spring as the potential energy.

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The potential energy of the spring. It states that for conservative forces the sum of kinetic and potential energy at any point remains constant throughout the motion.

Heat Energy- The total energy of an isolated system remains constant. Chemical Energy- The energy may change form but total energy in a chemical reaction remains constant.

## What is Work, Energy and Power?

Electrical Energy — The total electric charge of a system remains constant. Nuclear Energy- In a nuclear reaction total mass of the reactants or starting materials must be equal to the mass of the products.

The collision is the phenomenon in which two or more bodies come in physical contact with each other or it takes place when the path of one body is affected by the force exerted due to the other. Elastic collision- A collision in which both momentum and kinetic energy of the system remains conserved.

In this collision force involved in the interaction are of conservative in nature. Inelastic collision- A collision in which only the momentum of the system is conserved but the kinetic energy is not conserved.

## Work, Energy, and Power

In this collision, some or all of the forces involved are non-conservative in nature. Consider two balls A and B of masses m A and m B are collide elastically. Let us assume that the velocity of the ball A and B before the collision is u A and u B and after the collision is v A and v B. The velocity of the ball A after a collision,.

## Work, Energy, and Power Notes for IIT JEE, Download PDF!

The velocity of the ball B after a collision,. The velocity of both ball after the collision,.

## Work example problems - Work and energy - Physics - Khan Academy

Consider two balls A and B of masses m a and m b moving along X-axis with velocities u a and u b respectively. The coefficient of restitution - The ratio of the relative velocity of separation after collision to the relative velocity of collision before collision.

JEE Main Syllabus with weightage. Engg Exams.

Work, Energy, and Power Work Done by a Constant and Variable Force Work done by a Constant Force Work- The work done by a constant force is defined as the scalar product of force and the magnitude of displacement under the influence of force. Work is a scalar quantity. Kinetic energy, , where v is the velocity of the body Since both mass m and are always positive so KE is always positive and does not depend on the direction of motion of the body. The relation between kinetic energy and the momentum is, , where p is the momentum.

The graph between K and p is a parabola as shown below.

## What is Work?

The graph between and p is a straight line. Work-Energy Theorem The work-energy theorem by a constant force It states that the change in the kinetic energy of a particle is equal to the work done on it by the net force.

The work-energy theorem by a variable force Let us assume the variable force works from position x i to x f then according to the work-energy theorem the change in the kinetic energy is equals to the work done on by the variable force. Collision The collision is the phenomenon in which two or more bodies come in physical contact with each other or it takes place when the path of one body is affected by the force exerted due to the other.

Collision in one dimension Elastic Collision in one dimension Consider two balls A and B of masses m A and m B are collide elastically. The velocity of the ball A after a collision, The velocity of the ball B after a collision, Inelastic Collision in one dimension Consider two balls A and B of masses m A and m B are collide elastically.

Since the collision is elastic, kinetic energy is conserved.

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Then A ball dropped from height h and travelling a total distance S before coming to rest. Then, where e is the coefficient of restitution. Go Gradeup. Score Better. Avinash Kumar Don't quit, suffer now and live the rest of your life as a champion. Member since Feb