Sensing the speed of the mouse

Hello,

I am going to work on a game for my kids. Mot sure if it is a good idea for a game but it is an opportunity to learn more AS3. Anyway, Is there a way to run a function after the mouse has moved a certain speed for a certain amount of time? As if you were shaking somehting and then it explodes. Is there a way to even sense the speed of the mouse or would it be better to sense the number of times the mouse changes direction?

Any advice would be appreciated.