Answers

2014-11-08T15:03:51+05:30
Capacity for doing work is called energy. It may potential, kinetic, thermal, electrical, chemical etc.... capacity of a physical system to perform work. Energy will be in form of heat , light etc...

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a body capable of doing work, is said to possess energy. the energy possessed by a body is measured by amount of work that the body can perform. whe a body does work, its energy decreases, while if work is done on a body its energy increases.this means that there is always a transfer of energy whenever work is done. thus energy and work are related to each other . we can define energy as follows = the energy of a body is its capacity to do work and the S.I unit of energy is joule
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2014-11-08T15:08:44+05:30
Energy is the capacity to do work.
Different types of energy are: 
Light energy
Chemical energy
Electrical energy
Mechanical energy ( sum of potential and kinetic energy )

Potential energy is the energy possessed by an object due to virtue of its position and configuration.
PE=mgh
Kinetic energy is the energy possessed by an object due to its motion.
KE=1/2m*vsquare
The energy can be present in different forms.
For eg, heat, light, wind etc

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