lump disk mass to a point
hello
imagine a disk rotating by an axis that passes through the center of the disk
how can we find the analogue of a mass rotating by an axis?
I mean, how can we lump the whole mass of the wheel to a point?
how much will be the distance of this point from the axis?
for example to rotate a disk with radius 10 and mass 100 you need the same force as to rotate a point of mass 100 and rotation radius = ??
I suppose the radius will be some less than 10 (since not all parts of the disk are at this radius), but how much exactly?
thanks
PS: we need to do this in order to calculate other things, eg angular acceleration, etc
