PHYS 101 Lab 4 Worksheet v010522(1)

Both P1 and P2 carts collided at the same time, but P1 was moving and P2 was at a stop. As P1 cart slammed into P2, it suddenly started to accelerate. But as it gets to the end of the table, it stops and slows down. Table 2: P1 Data from v ( t ) Trial: Mass (kg) Initial Velocity Final Velocity Initial Momentum Final Momentum Initial Kinetic Energy Final Kinetic Energy 1 0.25 0 0.67 0 0.168 0 0.056 0 2 0.25 0 0.05 0 0.013 0 3.13*10^-4 0 Table 3: P2 Data from v ( t ) Trial:   Mass (kg)   Initial Velocity    Final Velocity   Initial Momentum   Final Momentum   Initial Kinetic Energy   Final Kinetic Energy   1    0.250  0  0.52  0  0.130  0  0.034  2    0.250  0  -0.55  0  0.138  0  0.039  he change in momentum and energy of the carts. Comment on how these values compare. Since P2 cart began at rest and moved as P1 cart collided with it, its momentum and kinetic energy are the same. Since the final momentum and kinetic energy for trial one are lower than the initial momentum for both trials, the change in momentum and kinetic energy is also lower. Table 4: P1 Change in momentum and energy Trial   Initial Momentum   Final Momentum   Change in momentum   Initial Kinetic Energy   Final Kinetic energy   Change in Kinetic Energy   1  0.168  0  -0.168  0.056  0  -0.056  2  0.013  0  -0.013  3.13*10^-4  0  -3.13*10^-4    Table 5: P2 Change in momentum and energy Trial   Initial Momentum   Final Momentum   Change in momentum   Initial Kinetic Energy   Final Kinetic energy   Change in Kinetic Energy   1  0  0.130  0.093  0  0.034  0.017   2  0  0.138  0.115  0  0.039  0.039  3

5. For trial 1: compare the change in momentum that cart 1 and cart 2 experienced, what do you notice about the change in momenta? What do you notice about the sum of the change in momenta? What would you expect the change in momentum to be for the system? Repeat for trial 2. Is this what you would expect from an INELASTIC collision? in trial 1, the momentum of car 1 decreased by 0.097 while the momentum of car 2 increased by 0.043. The total momenta change is -2.76 x 10-3. In trial 2, car 1's momentum dropped by 0.038 while it increased by 0.113 for car 2. Momenta collectively change by -2.53 x 10-2. Both momenta changes should be zero in the event of an inelastic collision. Although our results were nearly inelastic, indicating a collision that was nearly inelastic, we can still explain the small variations by potential human error. 6. For trail 1 and trial 2, comment on the change in kinetic energy before and after the collision (make sure to investigate the TOTAL energy before/after). Is this what you would expect for an INELASTIC collision? For trial 1, there was a loss of -0.034J due to the collision, with an initial total kinetic energy of 0.038 and a final total kinetic energy of 3.61*10-3. For trial 2, there was a loss of -2.76*10-3J due to the collision, with an initial total kinetic energy of 5.0*10-5 and a final total kinetic energy of 2.81*10-3. Our data supported our expectation that there would be a kinetic energy loss in an inelastic collision. 4. Analysis Questions: 1. What experimental evidence do you have showing that momentum is conserved in inelastic and elastic collisions? Our experimental results show that momentum is conserved in both elastic and inelastic collisions. Momenta changed by -0.038 in the elastic collision while they changed by roughly - 2.53 x 10-2 in the inelastic collision. Both of these numbers are very close to zero, which suggests that momentum is being conserved to a large extent. 2. How does your data support the conservation of kinetic energy in elastic collisions? energy is conserved in elastic collisions. Our data show that 0.034 J of kinetic energy were lost during the trial. The value is very close to the predicted loss of 0 J, even though it is not a perfect conservation, indicating that the lost energy was probably caused by outside forces or influences. 3. How does your data support the non-conservation of kinetic energy in inelastic collisions? In inelastic collisions, the conservation of kinetic energy does not hold true. Our collected data reveals a loss of -0.012 J of kinetic energy in the trials involving inelastic collisions.   6