boyntonstu wrote:I hope that this helps explain elasticity and Modulus of Elasticity.
I should note that you're trying to explain engineering to D_Hall... which, as the saying goes, is like teaching your grandmother to suck eggs (not that the saying makes much sense.)
Modulus of Elasticity is stress divided by strain. It tells you (as D_Hall said) the force needed to cause a certain deformation.
It is not a measure of the amount of energy retained in an inelastic collision (and on a macro scale, almost all collisions are to some degree inelastic) - the figure for that is coefficient of restitution.
The two are related however - the energy absorbed under deformation is equal to the area under the stress-strain curve. The energy released as deformation is "recovered" is also equal to the area under a stress-strain curve - but a different one with lesser stress, because energy has been lost to heat.
The coefficient of restitution is equal to the ratio of the area of the two curves for the appropriate time scale (in this case, time of impact, which is obviously dependent on velocity.)
