# How does weight/mass affect angular momentum?

How does weight/mass affect angular momentum?

For my 8th gr science fair project I have to do an experiment on angular momentum. My problem is that we have not been taught any of that in physics yet, nor will my teacher even explain it this year but she expects us to figure it out. After trying to understand a little by watching youtube videos, I thought that maybe I can recreate the figure iceskater example using a turntable and several types of weights. What I wanted to do is test and record (I must use an equation) how a 5lb.vs 10lb. hand weight affects how fast or slow the person spins with both arms outward and then bringing them in close to their body and maybe include a timer to record how many rotations they did in an amount of seconds or something like that. We were told a few days ago that the whole project is due this Thursday but now that I have all the materials, I'm not sure if this makes sense or not. I don't have the option to change my question altogether. I'm stumped on the equation part, and how to solve this problem.

• Hi Carol. Welcome to Physics.SE. Perhaps I must appreciate that your experiment seems to be looking good. Could you please rephrase your question to ask "what you really want?". Because, its somewhat paragraphy & catchy. Could you precise your question a little bit. Even I become lazy on looking at story-like questions :-) – Waffle's Crazy Peanut Dec 12 '12 at 7:52

Angular momentum is given by $L=Iw$ where $I$ is the moment of inertia. A turntable can be well approximated by a solid cylinder of radius $r$, height $h$ and mass $m$. Its moments of inertia are
$$I_z = \frac{mr^2}{2}$$
$$I_x = I_y = \frac{m}{12} \left(3r^2+h^2\right)$$
Now you can see what happens when $m \rightarrow 2m$.