21-Nov-2016: Lab 19 Conservation of Energy/Conservation of Angular Momentum

1. Title: Lab 19 Conservation of Energy/Conservation of Angular Momentum
    Name: Qiwen Ye (Sherry)
    Partners: Matt
    Date: 21-Nov-2016

2. Purpose
In this experiment, we need to use conservation of energy and conservation of angular momentum to predict how high a clay-stick combination should rise, then capture the experiment on video in order to compare actual results with predictions.

3. Theory
From the conservation of energy theorem, we could find an angular velocity of a meter stick before it hit the clay. Then, for the conservation of angular momentum, we could find the angular velocity after it hit the clay. Meanwhile, the clay stuck on the meter stick and they were moving together, it means that they have the same angular velocity. Last, used the conservation of energy theorem again to determent how height the clay-stick combination should go up.

4. Apparatus/Experimental procedure
Set up a system that released the meter stick, which rotated about one end (20 cm away from the end of the meter stick) from a horizontal position. After the meter stick reached the bottom of its swung it collides in elastically with a blob of clay. The meter stick and clay would stick together and continue to moving to its maximum height. Then, captured the experiment on video by camera and used Logger Pro to analysis the system movement in order to find the experimental maximum height.

5. Measured Data
By using the Logger Pro, we described the movement of the meter stick from horizontal position to its maximum height. Used a blue dot to record the movement of the meter stick in order to find what is it maximum height. While we put the dot to record the movement, it would create a table about the the height of the meter stick in its rotation.

According to that table, we found that the maximum height of the clay after collision was 0.2857 m. 

Here was the measurement about the meter stick and the clay:

6. Calculated Results

By using the conservation of energy and conservation of angular momentum theorem, we could find the maximum of the system in the rotation. Used the measurement to calculate angular velocity just before the stick hit the clay, when it was in its vertical position. Then, used the conservation of angular momentum equation to find the angular velocity hit. We got the maximum height of the clay was 0.3079 m.

7. Explanation
Compared to the theoretical and experimental value of the maximum height, we found that the different percent was 7.75.

8. Conclusion
In this experiment, we studied the conservation of energy and conservation of angular momentum to calculate the angular velocity before the meter stick and the clay collided and after collided. Also, determined the momentum of inertia of the meter stick and the clay while they were rotating about near one end of the meter stick. Used the conservation of energy again to find the maximum height of the combination of the system. The different of the experimental and theoretical value was 7.75%. The friction between the meter stick and the apparatus may cause the error percent. Or, we marked a dot of the system movement in Logger Pro, we may not that in the center. The center of mass of the clay may not have been exactly at the end of the meter stick.