I'm trying to design a spherical robot that uses wieghts on it's inside to jerk it around would this work?

As you know, there are toys that use a rotating weight to move a ball around. There is also a larger unit that operates from radio control that lets you control the direction, speed, and cornering of such a ball, so the answer is YES. I suggest starting with United States Patent 5439408 and going on from there.

This is 4 months after your post, but if you see it you might like this video:

http://www.imponderablethings.com/me/pics_and_vids/germ...nd%20the%20ball.html
picture of inside
http://www.imponderablethings.com/me/pics_and_vids/germ...20of%20Ball%201.html

It's a black ball that listens to music from the contra clarinet and rolls around according to pitch. It also has piezo electric drivers on the outer shell that turn the whole thing into a giant speaker. A computer sends audio via bluetooth or something wirelessly for it to play in real time based off the clarinet.

-Scott