1. The problem statement, all variables and given/known data A disk of radius 0.41 m and moment of inertia 2.8 kg·m2 is mounted on a nearly frictionless axle. A string is wrapped tightly around the disk, and you pull on the string with a constant force of 52 N. What is the magnitude of the torque? torque = 21.32 N·m After a short time the disk has reached an angular speed of 4 radians/s, rotating clockwise. What is the angular speed 0.63 seconds later? angular speed = ??? radians/s 2. Relevant equations torque = RFT Rotational angular momentum = (MR2/2)ω 3. The attempt at a solution The new angular momentum is the old angular momentum plus the angular impulse, torque times time interval. (2.8/2)4 + (21.32)(.63) = 19.03 radians/s However, this answers is wrong, and I can't figure out what I am doing wrong.