Skating and angular momentum!

Purpose/Problem Conservation of angular momentum is the principle that the angular momentum of an object remains constant as long as no external torque, or moment, acts on that object. When a figure skater is in the air, he or she is rotating about his or her center of mass and possess a certain amount of angular momentum. The only external force is gravity. However, gravity acts vertically down through the center of mass (COM) of the skater. Since gravity acts through the axis of rotation of the skater, it does not cause a torque and can not change the skater's angular momentum.In this project I’ll explore methods of finding how momentum changes in response to different variables.

Hypothesis I believe that the more weight that I put on my self the faster and longer the chair will spin, because it’ll carry it’s momentum much longer than something lighter. Something lighter would most likely lose its momentum in a short period of time.

Materials The materials I’m going to use are: Chair Weights

Variables Dependent Variable: How fast I go, how many revolutions I make. Independent Variable: The minute reactions the person spinning the chair makes. Controlled Variable: The environment I’m in, the materials I use.

Procedure I’ll conduct this experiment by spinning the chair for five seconds, and I’ll record how many revolutions I make in the following circumstances: Hands in lap Arms out Weight’s and arms out.

Qualitive Data The more I spun the chair the dizzier I got. The chair moved a similar amount of revolutions no matter what different variables I used.

Quantitative data Spins: Weights Folded hands Open arms 1st try 3 3 3 2nd try 3 4 4 3rd try 2 ½ 3 4

Graph Distribution graph.

Results There was a slight variation in the results. Not much but when I had my hands in my lap the chair rotated noticeably faster. So,my conclusion is that my momentum would carry me at a similar speed regardless of my position.

Pictures Me spinning in a chair with my arms out.

Pictures Me spinning with my arms in.

Conclusion Momentum stayed constant pretty much throughout, proving that a dramatic change in weight would be necessary to change the nature of the spin, or the amount of times it’d spin.