# Energy is

Avgiu
I have heard one definition of energy meaning a degree of inertial resistance... can anyone give me a different working condition for the word

moose
Degree of inertial resistance sounds more like mass to me... *shrug*

z-component
In physics, energy is the capability of something to do work. And yes, a "degree of inertial resistance" is mass.

Ki Man
yea degree of inertial resistance does sound like mass. but mass is energy according to E=MC^2 so i guess its right in a way. my pinky is energy along with my textbook and keyboard

blt93932
Matter is not energy, matter can become energy and vice vesa.

Gold Member
I'm not quite in agreement with that, but it might be just a matter of me using the wrong terminology. Given the wave functions involved, I always consider matter to be energy in a bound state, roughly analogous to ice being water in a bound state.

PatPwnt
Matter IS... another form of energy or vice versa

Homework Helper
"Energy" is a bookkeeping device (how many words do you know with three double letters in a row?). People noticed long ago that kinetic energy is conserved in simple collisions so developed "conservation of energy". Of course, if the collision is not "elastic" that doesn't work so they added "heat" as a type of energy to "explain" that (and keep "conservation of energy" true). When relativity made it clear that mass could be converted to energy (and vice-versa) mass itself was declared a kind of energy just to make "conservation of energy" still work!

pmb_phy
Avgiu said:
I have heard one definition of energy meaning a degree of inertial resistance... can anyone give me a different working condition for the word
The term Inertial resistance has never been defined in physics. Let me offer this;

inertia is defined as the amount by which a body resists changes in momentum. So what would you call something which resist a change in momentum? I'd call that "force" in that F = dp/dt.

The definition of energy is given here

http://www.geocities.com/physics_world/mech/what_is_energy.htm

Pete