Rotational Motion

Dave

If an object is rotating i.e. a disc, the further you go from the edge the velocity decreases. So theoretically does this go on for infinity or is there some point that isn't rotating and if so how does the whole disc rotate.

dudara

I don't quite get what you're asking.

linear velocity = (angular velocity)(radius)

For a constant angular rotation rate, as you move away from the centre, the linear velocity increases. At the exact centre, there is zero linear velocity. What you mean by infinity?

Dave

If there is a zero linear velocity then how is the surrounding area moving?

dudara

Because it's at the exact centre or an infinitesimal pinpoint where there is zero velocity. it's an ideal.

In reality every particle will have some r-vector, no matter how small, and therefore an associated linear velocity.

Dave

Originally posted by dudara
Because it's at the exact centre or an infinitesimal pinpoint where there is zero velocity. it's an ideal.

That's what I was referring to when I said infinite.

dudara

OK, i get you now, but infinite has a different meaning to infinitesimal