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The Coefficient of Restitution
| 1.
Preparation: |
a) Make
sure you know what is meant by relative velocity. |
|
b) See part 4
below. |
| 2. |
When two
objects collide, their coefficient of restitution gives a
measure of the elasticity of the collision. An elastic collision
is one in which kinetic energy is conserved. In practice some
k.e. is always converted into other forms. Which other forms?
If we compare the relative velocity of the two objects just
before the collision (velocity of approach, va) with
their relative velocity just after the collision
(velocity of separation, vs) we can see "how
elastic" the collision was. |
|
Coefficient of
restitution = e |
|
e = vs/va |
|
e = 1 for totally
elastic collision
e = 0 for totally inelastic collision |
| 3. |
Experiment
to estimate the Coefficient of Restitution for a ball bouncing on
the laboratory bench |
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|
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Two horizontal rods will
be found helpful in estimating the heights h1 and h2
(as shown in the diagram). |
| 4.
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Your final
value for e must be taken from a suitable graph. |
|
© David
Hoult 2008 |
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Open Door Web Site