Add to that the fact that the skin is not perfectly elastic, even in the young.

The behaviour shown in the first figure refers to a perfectly elastic material, such as steel.

"Air's a perfectly elastic fluid," roars George above the tumult.

However, some problems are sufficiently close to perfectly elastic that they can be approximated as such.

Generally, soil deposits are not homogeneous, perfectly elastic, and isotropic.

In a perfectly competitive market, a firm's demand curve is perfectly elastic.

In an ideal gas, these collisions are perfectly elastic.

The demand curve for a PC company is perfectly elastic - flat.

String should be perfectly elastic in the range of Floyd Rose action.

The same is true of perfectly elastic billiard balls on a frictionless surface.