PIRA 1N30.49
| This demonstration of momentum transfer uses the
Arbour "Happy" and "Sad" balls.
These balls are vulcanized rubber. At room
temperature, the "Happy" ball has a large
coefficient of restitution (it bounces good), while the
"Sad" ball has a coefficient of restitution of
almost zero (it doesn't bounce). Both balls are of
the same size and mass. Adjust the Recoil ramp so
that when rolled from the top, the "Sad" ball
barely fails to knock the Recoil Board over. Be
sure to set this up before class. Otherwise it may
look like you are deliberately rigging the demo (which
you are). Ask your students which ball is more likely to knock the board over. Many are surprised to see the "Happy" ball topple the board when the "Sad " ball failed. This is a very clear demo of the fact that recoiling objects transfer more momentum than those that don't. |
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