Hi! Please follow the link; its a guy juggling balls in an inverted cone. What he does is he uses the cone as a surface, and he rolls the balls around him in circles. ITs really entertaining so this shouldn't be too much of a chore. I thought I'd post it here because it demonstrates simple angular mechanics quite well. I was wondering however, how would we calculate the time it takes for the ball to reach the bottom of the cone, if lets say, the ball is projected with an initial horizontal velocity of u at a height L. Gravity accelerates the ball downwards. And to simplify, we neglect friction. I've attached what I've managed to do, which isn't much... I wasn't sure if angular momentum is conserved... And wasn't so sure how to incorporate weight into the calculation. Can someone help me solve the problem? Its killing me. I'm a 2nd year engineering student. Anyone would think I'd be able to handle a problem like this, but looky, I can't. I'm an idiot.