What is energy?

ENERGY - energy of a body is defined as its capacity to do work. it is a scalar quantity. UNIT OF ENERGY - as energy is defined as the amount of work that a body can do, so the unit of energy is same as that work.the SI unit of energy is joule(J). one joule of energy is the energy required to do 1 J of work. FORMS OF ENERGY - mechanical energy (kinetic and potential) , sound energy< heat energy , light energy , chemical energy, nuclear energy , electric energy , magnetic energy , solar energy , etc. LAW OF CONSERVAION OF ENERGY - Energy can neither be created nor destroyed. it can be transformed from one form to another. the total energy before and afterthe transformation always remains constant. POWER- the rate of doing work is called power WATT - it is the SI unit of power