Definition Of Energy

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