Work-Energy And Power Class 11 Notes PDF

Work, power, and energy are among the most important concepts of mechanics. A moving car, walking up stairs, lifting heavy objects, an airplane flying, etc are among the most common examples that give us insight into the concept of work, power, and energy. There are few common notions of work, power, and energy that can be precisely defined in physics. These notions and measurements can be utilized to define and predict the motion and behavior of bodies.

What is Work?

Work is the measurement of energy transfer that takes place when an object is displaced by an external force applied in the direction of the displacement.

What is Power?

The rate of doing work is called power.

What is Energy?

The capacity for doing work is called Energy. It may exist in kinetic, potential, thermal, chemical, electrical, nuclear, or various other forms. The SI unit of energy is the same as that of work.

What is the Principle of Conservation of Energy?

The Principle related to the conservation of mechanical energy states that the total mechanical energy of a substance remains in equilibrium if the only forces acting upon the body are conservative in nature.

Important Questions

  1. The sign of work done by a force on a body is important to understand. State carefully if the following quantities are positive or negative:
  • (a) work done by a man in lifting a bucket out of a well by means of a rope tied to the bucket.
  • (b) work done by gravitational force in the above case,
  • (c) work done by friction on a body sliding down an inclined plane,
  • (d) work done by an applied force on a body moving on a rough horizontal plane with uniform velocity,
  • (e) work done by the resistive force of air on a vibrating pendulum in bringing it to rest.
  1. Underline the correct alternative :
  • (a) When a conservative force does positive work on a body, the potential energy of the body increases/decreases/remains unaltered.
  • (b) Work done by a body against friction always results in a loss of its kinetic/potential energy.
  • (c) The rate of change of total momentum of a many-particle system is proportional to the external force/sum of the internal forces on the system.
  • (d) In an inelastic collision of two bodies, the quantities which do not change after the collision is the total kinetic energy/total linear momentum/total energy of the system of two bodies.

These work energy and power class 11 notes pdf can be viewed below:

The students can prepare all the important concepts included in this unit by referring to the work energy and power class 11 notes pdf from the links mentioned below:

  • Work Energy and Power Class 11 notes pdf
  • Energy
  • Work
  • Types of Energy
  • Heat Energy and Internal Energy
  • Different Forms Of Energy
  • Power
  • Conventional and Non-conventional Energy Sources
  • Kinetic Energy
  • Electric Power
  • Potential energy

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Practise This Question

The Undertaker brags about stopping a moving car with bare hands. To prove himself he stands infront of a moving car coming towards him and surprisingly stops the car in 10 seconds after initial contact.The work done by him in this duration will be