hi, thanks for your help.
so as i understand with increasing radius increases moment of inertia.the moment of inertia of an object is a measure of how difficult it is to start it spinning. and as i imagine it,some parts of the iron ball are closer to the axis, therefore it has smaller moment...
two balls, one made of iron and one made of lead with same radius and mass. which one will roll down the slope faster?
i don't really know where to begin, since everything is the same, the only idea i had was to somehow relate Ek=(J.ω2)/2 => Ek= m.r2.(ω2/2) to the question since i imagine...