20 May 2015. Conservation of Angular Momentum

Purpose
to observe the conservation of angular momentum (from kinetic to potential) of a meter-stick and a clay.

Apparatus:

A set up shown in the picture. There is this meter-stick that is going to be released parallel to the floor, and purposedly aim to hit a clay in the floor. We are going to measure the kinetic energy that is going to be transformed to potential.

Procedure

1. We set up the apparatus as follow.
2. Then, we align the camera right in the middle of the impact.

3. Weight the mass of the clay and the ruler.

4. Record all the data.

Data Analysis:

• Now, for the experimentally part, we can analyze the video capture, set the origin, and add one point series for the height.

h = 0.2904 m

• For the true value: For the first section, we use conservation of energy to calculate the angular speed right before the impact of the clay.

• Then for the impact, we can find the omega final (ruler+clay).

• Then, we use conservation of energy again to determine the final height.

so the height is 0.401 m

• So the percent error is: (0.401-0.2904)/0.401*100% = 27.58%

Conclusions

• We manage to find the height using the law of conservation of energy and angular momentum.
• The percent error is quite huge, around 25%.
• These errors are quite not surprising, for this reason:
• The fact that the energy is really conserved in this collision. It transformed to heat and sound, not only the height.
• Uncertainties in measuring length and mass of the ruler and clay.
• Rounding significant figures.