Question

why is work equal to change in kinetic energy??? explain in easy words...plz fast...urgent..

Answer 1

   Total energy = KE + P.E. + Thermal Energy + Electrical Potential energy + ...

     Energy is said to be the capacity to do work.  Generally work is done by physi cal movement of a body.  Hence, the kinetic energy is involved.  When the potential energy changes, that is converted usually into the kinetic energy.  However, there is no work done that case.

   Usually, moving object does work.  Hence the decrease or increase in the kinetic energy is the amount of work done by the body or the external agent respectively.  Other components of energy remaining same.   Other energies convert to kinetic energy and kinetic energy does work.

     Work is done when a force moves (or slows down) a body through a distance.  Then kinetic energy is changed.  Also, work is done when a gas expands or compresses varying in pressure and volume.  When a spring is  compressed, there is work done, but by movement of some object or absorbing kinetic energy of an agent.