Definition of Energy

"The capacity to do work is called energy".
Energy is numerically equal to the work done.
Energy = Work done.

More About Energy

  • While doing a work one form of energy is converted into another.

  • While winding a spring the mechanical energy is converted into the potential energy of the spring.
    While moving an object the mechanical energy is converted into the kinetic energy of the body.

  • If the work done is W, then the energy is also W.
  • The unit of energy is same as that of work, i.e., joule.
  • Types of Energy:
  • 1. Kinetic Energy
    2. Potential Energy
    3. Mechanical Energy
    4. Chemical Energy
    5. Thermal Energy

Solved Example on Energy:

A force 30N is applied on w body and the body moved a distance 5 m, then the energy is
    A. 30J
    B. 30J
    C. 300J
    D. 150J

    Correct answer is D.


    Step 1: Energy =work done. W = f.dx
    Step 2: Insert the value of the force and displacement, in Newtons, and distance in meters = 30 � 5
    Step 3: Write down the final answer in joules.
    Step 4: W=150j

Related Terms: Energy | Work
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