# Verification of the Principle of Conservation of Momentum

In this experiment a trolley is pushed down a runway which is tilted at an angle so that the speed of the trolley remains constant. It then collides with and sticks to a second trolley and they travel together to the end of the runway. The velocity of the trolley is measured just before and after the collision. If the masses of both trolleys are known the momentum before and after the collision can be calculated. Momentum = (mass)(velocity) Note: In this simulation the mass of each trolley is 1 kg and the moveable masses are each 0.2 kg.

Procedure:
1. Note the mass on each trolley

2. Press "Push Trolley".

3. Press "Get Tape and Ruler".

4. Measure and record a five-space distance (5/50 s) just before collision.

5. Calculate "u" = distance/0.1. Calculate "v" in a similar way after collision.

6. Press "Reset".

7. Press "Move Mass" and repeat steps 1 to 6 until the three masses have been transferred to trolley 2

Analysis:
For each collision calculate the momentum before the collision and the momentum after. The results, subject to small experimental error, should be equal thus verifying the principle of conservation of momentum.
Precautions:

• Ensure that the runway is tilted just enough for the trolleys to roll at constant speed when given a gentle push.
• Ignore a few dots on either side of the collision. These may be unreliable.
• Place a ruler right on top of the tape with eye directly above when measuring distances to avoid parallax errors

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