# B Does the coefficient of restitution depend on the collision "type"?

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1. Dec 2, 2017

### erfz

Probably a very simple question:

Does the coefficient of restitution depend on the collision being performed?

Consider two masses $m_1$ and $m_2$. They are placed on a frictionless horizontal table and $m_1$ is given an initial velocity, collides 1-dimensionally with $m_2$, and the coefficient of restitution is calculated from the initial and final velocities.

If instead I had $m_2$ on a table and $m_1$ was dropped from a height $h_i$ onto $m_2$, and then came up to a height $h_f$, would the calculated coefficient of restitution be the same here as in the first situation?

2. Dec 2, 2017

### PeroK

If you dropped one mass from high enough, then possibly the objects would break apart, rather than bounce off each other.

This suggests to me that the coefficient of restitution for two objects would tend to be approximately constant across a limited range of collision velocities, but in general a single coefficient would not apply across all possible collisions.

3. Dec 2, 2017

### erfz

But assuming that they do not break, the coefficient can be applied to both scenarios?

4. Dec 2, 2017

### PeroK

In general you may get cracks or permanent deformations, which I suspect will be non-linear in nature.

Have you tried looking online for articles on experiments looking at this?

5. Dec 2, 2017

### erfz

No, but that is a good idea.
Thank you!