Physics 105

April 28, 2003

Today we will finish analyzing our collision experiments. Each person must have analyzed the collisions in which he/she was involved. For each collision you should have determined:
• The momenta of the carts (+students) before and after the collision
• The kinetic energies of the carts (+students) before and after the collision

For each collision you should have determined these values and their errors. For each collision, look at the following issues:

• Is momentum conserved (e.g. is the difference in the momentum before and after the collision consistent with the errors in the measurement)?
• How much kinetic energy is lost in the collision?

For those collisions in which there is a "huge" difference between the momentum before and the momentum after the collision, we need to make sure that no obvious errors were made in the analysis (e.g. the wrongs mass is assigned to students involved in the collision).

After verifying the quality of the data, we are ready to start looking at the correlation between the loss in kinetic energy and the deformation of the cans.

Today we will focus in more detail on the actual deformation of the cans. It is reasonable to assume that the energy required to deform the cans increases with increasing deformation. The first two models we will consider to relate the deformation to the loss of kinetic energy make the following assumptions:

• The energy required to deform the can is proportional to the deformation.
• The energy required to deform the can is proportional to the square of the deformation.

Use all 18 collisions to determine whether or not the observed correlations can be described by these models. If not, can you develop another model which can describe the data we collected?

© Frank L. H. Wolfs, University of Rochester, Rochester, NY 14627, USA

Last updated on Wednesday, April 23, 2003 4:41