Let's say I have a stone tied to a string and I'm spinning it vertically. Now, if I provide an initial velocity such that the velocity of the stone = 0 at an angle greater than 0 from the horizontal(visualize it in the "first quadrant") the eq of motion would be: T+mgsin (theta) = mv^2/r. If the velocity equals zero, then tension would end up negative which is not possible. Hence I've come to the conclusion that as soon as The T =0(which would happen before v =0), the stone would exit circular motion and travel somewhat like a projectile. So basically, in the "first quadrant", it's not possible for v to end up 0 while remaining in circular motion since T would = 0 before V would equal 0 and hence the stone would exit circular motion. Is this correct?