work , energy and potential

[nouveau_riche]

well to begin with the fundamental definition of work and energy,i found a flaws in one

 

energy is capacity of doing work

work is the transfer of energy that takes place under the effect of force,in the direction of displacement vector

potential is the ability of doing work but the working element may not be at action at present

 

firstly how is energy different from potential?

secondly work done by magnetic forces is zero but there is energy involved which counters the above definition?

[timo]

firstly how is energy different from potential?

Energy terms can come in a variety of forms. One of them is potential energy. Potential is the potential energy of a particle divided by the charge of the particle (where "charge" is not necessarily the electric charge; in case of a gravitational potential it is the mass). Some people do not understand the difference between potential and potential energy and say "potential" when they in fact talk about the "potential energy".

 

secondly work done by magnetic forces is zero but there is energy involved which counters the above definition?

I dunno? Considering you are the one wanting to prove school physics wrong I think you should provide the actual example. Not every force has an associated potential, anyways.

Edited August 26, 2011 by timo

[swansont]

secondly work done by magnetic forces is zero but there is energy involved which counters the above definition?

Zero work means no change in the energy. It doesn't mean the object has no energy.

[nouveau_riche]

Zero work means no change in the energy. It doesn't mean the object has no energy.

 

but the definition given for energy is "capability of doing work"

[swansont]

but the definition given for energy is "capability of doing work"

The charged particle can do work, so it can have energy, regardless of the presence of a magnetic field. The magnetic field can't do work on the charged particle.