Work, Energy and Power


   
 
Kinetic Energy
Energy
 
Energy is a number that we associate with a system of one or more objects. If a force acts on one of the objects, making it move, then the number changes. After countless experiments, scientists and engineers realised that if the scheme by which we assign these energy numbers is planned carefully, then the numbers can be used to predict the outcome of experiments. However, learning how to use the numbering scheme is not easy. Let us focus on one form of energy - kinetic energy.
 
 
Kinetic energies
A dancing or running man is said to be more energetic than a sleeping man. In physics, a moving particle is said to have a more energy than an identical particle at rest. Quantitatively, the energy of the moving particle is given by
 
 
The kinetic energy of a system of particles is the sum of the kinetic energy of all its constituent particles, given by
 
 
If no force is applied on a particle, its velocity 'v' remains constant
 
Example
 
1) A bullet fired from a gun can pierce a target on account of the kinetic energy of the bullet.
 
2) Windmills work on the kinetic energy of air.
 
 
     
   
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