Physics decceleration algorithm needed

For a solid spinning cylinder to accelerate(/deccelerate) a force, F, has to act on the cylinder at some distance, d, from the axis around which the cylinder is spinning.

I: the moment of inertia of a solid cylinder

α: the angular acceleration

m: the mass of the cylinder

r: the radius of the cylinder

I = ½mr²

M = Fd

α = M / I

⇒

α = 2Fd / mr²

if F is acting on the surface of the cylinder (i.e. d=r) then α = 2F / mr

And then you get a new angular velocity, ω′, like this:

ω′ = ω + αt

If the cylinder is shallow instead and has a very thin wall then:

I = mr²

and if the wall of the cylinder has the thickness w, then:

I = ½m(r² + (r-w)²)

- Marcus Sundman

msundman at 2007-7-7 14:08:35 >