Lab #4 - Angular Momentum: Demonstrating the Law of Conservation of Angular Momentum

Objective

Objective:
The purpose of this lab is to demonstrate the law of conservation of angular momentum. Specifically, it demonstrates the way in which this law affects the relationship between moment of inertia and angular velocity and provides a practical basis for understanding the basic principles related to angular momentum. To complete this assignment, you’ll need to watch the video for Lab #4 (and conduct the experiment yourself if you can) and answer the questions below. Make sure your answers to the questions are complete, concise and well constructed. Do not answer in point form.  Your answer should describe and explain the phenomena you observed and demonstrate that you have a thorough understanding of the principles involved.
Experiment 1:

Watch the video Lab #4 – Angular Momentum and find an object that you can stand or sit on that will spin freely (i.e., an office chair or fitness turntable; e.g., http://www.aliexpress.com/item/Magnet-Balance-Rotating-Trimmer-Fitness-Core-Waist-Twisting-Disc-Weight-Loss-Fitness-Equipments-Twister-Plate-turntable/32268258532.html). To perform the experiment yourself, abduct both arms to 90 degrees (relative to your body) so that they’re horizontal (parallel) to the floor. Spin yourself or have a partner grab one of your arms and slowly rotate you in either the clockwise or counterclockwise direction.  Once you’ve completed approx. ½ a revolution, pull your arms in towards your chest as quickly as possible for several seconds before returning your arms to their original position.  Repeat the procedure several times. Describe in detail exactly what happens. Explain why this behaviour occurs.
Experiment 2:

Repeat Experiment #1 holding a 5 lb. weight in each hand. Try to initiate the rotation at the same speed as in Experiment #1.  Describe how this behaviour compares with the behaviour in Experiment #1.  Explain why it is different.
Experiment 3:

Stand on the turntable in the anatomical position (or sit in the chair with your arms and legs extended and your feet off the floor). Hold a 5 lb. weight in each hand and as before, abduct both arms 90 degrees so that they’re parallel to the floor. With your arms, initiate a forceful negative (clockwise) trunk rotation by horizontally adducting your left arm 90 degrees about the longitudinal axis to the midline while moving your right arm in the same direction. Repeat this motion in the opposite direction (i.e., initiate a + rotation). Describe what happens in each case. Provide an explanation for the phenomena you observed.

Experiments 1, 2 & 3:

Explain how all of the above experiments demonstrate the principle of conservation of angular momentum. In what circumstances does this principle not apply? Provide an example from one of the experiments. (