A playground ride consists of a disk of mass M = 46 kg and radius R = 2.0 m mounted on a low-friction axle. A child of mass m = 19 kg runs at speed v = 2.3 m/s on a line tangential to the disk and jumps onto the outer edge of the disk. What is the angular speed? I found the total angular momentum and used L_rot = I*w. Didn't work =/ Since the disk does not move, does that mean that L_total = L_rot? Or am I not getting something about L_trans? Cuz I assumed L_trans is zero because the system isn't moving.