Hello, An object moves outward in shaft radially due to centrifugal force. lest say it weights 1kg . in a timestep=0.0001 it travels 0.0017 meters this is actually the difference of two radius, let say first radius r1 = 0.25 meters second r2 = 0.25 + 0.0017 meters rpm of the rotating system is: 500.0 velocity difference by the distance it travelled from r1 to r2 vd = ((500 / 60.0 * r1*2.0*pi) - (500 / 60.0 * r2*2.0*pi)) now this velocity have to be delivered to the system by decelerating it. What would be the torque? v=a*t a=v/t = vd/timestep f = m*a T = f * r2 (its ok to use the higher one not much difference) the problem is that it makes pretty big anti torque, it seems that it is impossible even for the timesteps.. in a system 0.5kg moving outwards with the same velocity would create like 100+ NM anti torque which seems too much work for such a small object. My question would be then that is it valid to calc this way or any other valid ways? Thanks.