Science Buddies: "Ask an Expert"

My topics is similar to the project idea "How Long Will My Sleepy Yo-yo Sleep?".

http://sciencebuddies.com/science-fair- ... g&from=TSW

I have some questions relating to it. This project is dealing with so many physics concepts, but i am not sure what is main concept behind it . I am done with the experiment. My professor requires that i have to analyze my data by using calculations to prove the physics concepts behind the sleeping time of yoyo related to the string length. But i don't know which physics equations i could use to do the calculations. And then, after calculation, i have to do the error analysis , and i also don't sure which can make this experiment wrong. I am trying to research about those problems but i can't get the answer.So would you please help me out. Thanks a lot

Hi

The key concepts pf ypyp sleep are discussed in the project writeup. To find this writeup click on the Science Buddies Home tab at the top left of this page. Then enter YOYO sleep time in the serach box on the right top of the page and search. The top search result will be the project writeup. You need to understand angular momentum, Kinetoc energy and potential energy..

Good luck and have a great project!

Best regardss,

Barrett L. Tomlinson

Hey,

It might be difficult to have to teach yourself the required physics, but if you're up to it there's no reason why you can't!

Check out this website for more specifics on a yo-yo:
http://entertainment.howstuffworks.com/yo-yo2.htm

For sleeping time: To put it simply, "If you increase the moment of inertia in a yo-yo's discs, the yo-yo will be able to sleep longer; it takes more work to stop the rotation."

But what is moment of inertia?
It is a measure of an object's resistance to changes in the rate of ROTATION. It is similar to mass (which is a resistance to a change in linear motion), but more specifically applies to rotation.

In fact, linear and rotational motion can be explained by a set of equations that are extremely similar:
http://hyperphysics.phy-astr.gsu.edu/HBASE/mi.html