Angular Momentum (kg m2/s)
(in red above the rotating ball)
1. Using the data you have gathered and your knowledge of the law of conservation of angular momentum, explain the results for the angular momentum data column.
- The angular momentum of a rigid object is defined as the product of the moment of inertia and the angular velocity. All parts of the isolated system were held constant. Since there was no external torque on the object, the angular momentum could not have changed.
2. Find line or curve of best fit. What is the constant for this graph? Refer to lesson 1.13 for tips.
- The constant is 9.5036.
3. Using your knowledge of graphs, describe the relationship between radial distance and tangential velocity.
- Radial distance and tangential velocity have an inverse relationship. As radial distance increases, tangential velocity decreases.
4. Visit the following site: Conservation of Angular Momentum Demonstration. Play the video. Explain the changes in the woman’s speed as she moves her arms.
- While her arms are pulled in, there is a small moment of inertia. This is because only a small amount of torque needed to move the arms. Since angular momentum stays the same, and angular momentum equals the moment of inertia multiplied by angular velocity, the angular velocity must increase. This therefore causes an increase in speed. The opposite is true if the woman’s arms are extended.
This lab was performed in order to explore the conservation of angular momentum in a virtual lab setting. It was determined that angular momentum stayed constant and tangential velocity increased as the radial distance decreased. The slope of the trend line for the graph “Tangential Velocity Versus Radial Distance” was found to be -11.428. This shows that radial distance has an inverse