In this lab you will investigate elastic and inelastic collisions between two carts on a track. In elastic collisions the carts bounce off each other and in inelastic collisions they stick together. The momentum of an object is the product of its mass and its velocity, p = mv. If external forces acting in the horizontal direction (such as friction) can be ignored in the experiments of this lab, then the sum of the momenta of the two carts prior to a collision should be the same as the sum of the momenta of the carts after the collision. You will explore the implication of momentum conservation under various collision conditions.
Procedure:
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Experiment 1: An elastic collision Before the collision cart 1 travels towards the left and cart 2 travels towards the right. During the collision they reverse their directions. Determine the momentum of each cart and the total momentum of both carts before and after the collision. If friction were completely negligible, the total momentum should not change. With a small amount of friction present. its magnitude probably decreases, but only by a small amount. |
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Experiment 2:
Another elastic collision Before the collision cart 1 travels towards the left and cart 2 travels towards the right. During the collision they reverse their directions. Determine the momentum of each cart and the total momentum of both carts before and after the collision. If friction were completely negligible, the total momentum should not change. With a small amount of friction present. its magnitude probably decreases, but only by a small amount. |
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Experiment 3: A inelastic collision Before the collision cart 1 travels towards the left and cart 2 travels towards the right. After the collision they stick together and travel with the same speed towards the left.. Determine the momentum of each cart and the total momentum of both carts before and after the collision. If friction were completely negligible, the total momentum should not change. With a small amount of friction present. its magnitude probably decreases, but only by a small amount. |
Think about your result!
| Does the total momentum of the carts change in the elastic collision experiments? |
| Does the total momentum of the carts change in the inelastic collision experiment? |
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Did your experiments reproduce the expected results? If not, speculate on the reasons for any discrepancies. |