hi, if a motor spins a ball on a string round and round and a constant speed, there is an acceleration towards the centre, but no angular acceleration, just angular speed right? but if you now turn the motor off, the balls angular acceleration will now go negative, and the ball will decelerate. at what point does the ball fall. how do you calculate how long it will take and at what speed the ball will fall at? because this is seperate from its centrepetal acc yes?