Mechanical Engineering - Engineering Mechanics - Discussion

COR of Elastic bodies is 0-1 and for perfectly elastic is 1. So, the given answer is correct.

COR for perfectly elastic bodies will 1 only, hence answer of this question will be A not B.

"Perfectly" elastic body e=1.

The coefficient of restitution is the ratio of the final to initial relative velocity between two objects after they collide. It normally ranges from 0 to 1 where 1 would be a perfectly elastic collision. A perfectly inelastic collision has a coefficient of 0, but a 0 value does not have to be perfectly inelastic.

It is the ratio of final to initiate relative velocity between two bodies after they collide. For perfectly elastic body COR is 1.

The coefficient is 1 for an elastic collision, less than 1 for an inelastic collision, zero for a completely inelastic collision, and greater than 1 for a superelastic collision.

e = 0 for inelastic.
e=1 for elastic.

Elastic body means it regain its original shape & size. But in actual practice it doesn't regain its dimensions 100%. If it regain its dimensions perfectly (100%) then it said to be perfect elastic body & its coefficient of restitution is one. The plastic body has zero coefficient of restitution because it doesn't regain its shape & size. And normal elastic body regain dimensions but not perfectly hence it's coefficient of restitution is variable but less than one.

What is mean by momentum.

Impact Collision of elastic bodies.

If perfectly plastic body then its collision of restitution is e = 0.
Because of plasticity the body won't regain to its original shape it will continue with its deformation.

So, e = (v2 * -v1 *)/(v2 - v1).

Due to plasticity the body wont go under elasticity, eg clay, if u through 2 clay to hit opposite and each other it wont have any (V2 * -V1 *) so it zero.
e = 0/(v2 - v1) => e = 0.

If perfectly elastic then (v2 * -v1*) = (v2 - v1).
Therefor e = (v2 * -v1*)/(v2 - v1),
= (v2 - v1)/(v2 - v1),
= 1.