What is Energy? (ME-107 : Energy)

The word 'Energy' is derived from two Greek words 'en' and 'ergon'. In English 'en' means 'in' and 'ergon' means 'work'.

According to the origin, 'what' that is used or needed in (order to) work is called 'Energy'. The normal technical definition is ,"Energy is the capability or ability to do work". 'To do work" means moving something against a resistive force. We can only ensure the presence of energy if any work is made using it (as per technical definition).


Mathematically, Work is multiple of applied force and distance gained under that force.

Work = Force x Distance

W = Fs
or
W = FsCosθ

Physics says an energy is never ended up. It just converts itself into another form. There are several forms of energy:

• Chemical energy
• Elastic potential energy
• Electrical energy
• Electromagnetic energy
• Electrostatic energy
• Gravitational energy
• Heat energy
• Ionization energy
• Kinetic energy
• Light energy
• Mechanical energy
• Mechanical work
• Magnetic energy
• Nuclear energy
• Potential energy
• Solar energy
• Sound energy
• Surface energy
• Thermal energy

According to the first law of thermodynamics: "Total quantity of energy is always conserved."