Conservation+of+Momentum+Lab

=Lab: What is the relationship between the initial momentum and final momentum of a system?=

Objective: To design a situation where 2 carts of unequal mass hit barriers simultaneously.

Materials: 2 carts, masses, 2-m dynamics track, photogate timers, Smart Timer, picket fences.

Introduction/Theory This experiment demonstrates the conservation of momentum during an explosion, this is accomplished by calculating the momentum of two carts pushing away from each other. When two carts push away from each other and no net force exists, the total momentum of both cars is conserved. Because the system is initially at rest, the final momentum of the two carts must be equal in magnitude and opposite in direction so the resulting total momentum of the system is still ZERO.

Procedure: 1. Measure the mass of the carts, m1 and m2. Both should have picket fences on them.

2. Level the track by setting a cart on the track to see which way it rolls, Adjust the leveling feet to raise or lower the ends until a cart placed at rest on the track will not move.

3. Draw a labeled sketch of the situation.

4. Place the two carts against each other with the plunger of the Dynamics Cart pushed completely in and latched in its maximum position.

5. Adjust the position of the photogate timers so that the carts will trigger them immediately after they are released. Set the smart timers to measure velocity with one gate.

6. Push the plunger release button with a short stick and record the velocity of each cart. Repeat this trial 5 times.

7. Repeat for each of the cases described in the Data Table.

Calculations 1. Make a calculations table to organize your analysis. 2. For each of the cases, calculate the average measured velocity. 3. Using the velocity of cart 1 as a given, calculate the velocity of cart 2. 4. Find the percent difference between the measured and calculated velocity of cart 2.

Analysis Questions 1. Is momentum conserved in this experiment? Explain, using actual data from the lab. 2. When carts of unequal masses push away from each other, which cart has a higher velocity? Explain why this is. 3. When carts of unequal masses push away from each other, which cart has more momentum? 4. Is the momentum dependent on which cart has its plunger cocked? Explain why or why not.