Lab 19: Conservation of Energy/Conservation of Angular Momentum

Lab 19: Conservation of Energy/Conservation of Angular Momentum

Authors: Lab conducted by Mohammed Karim, Richard, and Lynel.

Objective: Compare experimental and theoretical results to the height that the clay/meter stick system raise to.

Theory/Intro: Using energy and angular momentum, we can calculate the height that the meter stick rises to. Now, we test our mastery in two physics concepts and see how accurate our calculations can be.

Apparatus/Procedure:

               Pic of apparatus

               The lab is set up to contain a meter stick, pivoted at the 10-cm mark, dropped from a height of 0.4m. It then collides with some clay and raises to a certain height. This can be calculated by splitting the problem into three parts. The first part is using the energy theorem to calculate the angular speed at which the meter stick hits the clay. (See Figure 19.1) Next, we calculate the final angular speed after the collision through conservation of angular momentum. (See Figure 19.1) Once we have the angular speed, we then calculate height by using the energy theorem once again. (See Figure 19.2) After calculating a theoretical value for height (0.3m), we put our math to the test and used motion tracking to calculate the maximum height of the meter stick and were able to come up with an experimental value of 0.363.

Data Tables/Analysis:

Figure 19.1 - Contains conservation of energy part 1 and conservation of angular momentum. For cons of energy, we found an omega. We used that omega in our angular momentum equation.

Figure 19.2 - Once we have the omega final, we plug it in to one last conservation of energy equation. This equation is done to calculate the height of the clay-stick system.

Conclusion: Our data came out pretty accurate. However, it is surprising that our experimental data was greater than our theoretical data. Usually, when conducting our experiments, our experimental data is typically smaller due to neglecting friction or some factor. However, this time it seems to be greater. My hypothesis is that the error is a result of multiple factors. For one, there could have been a slight intial force given to the meter stick as opposed to it being released from rest. Another reason could be that our points were not plotted at the exact center of mass of the meter stick/clay system. Alternatively, our collision may have altered it. Although it was an actual collision, the stick was mainly from the adhesive tape. However, I wouldn’t be too confident in saying that would result in the stick going much higher. Lastly, there is the consistent rounding error, but that would account for a very minor error.