I've been trying this problem for a while now and can't seem to get the given answer. I know I'm probably making an elementary mistake somewhere but I can't find it. 1. The problem statement, all variables and given/known data A track is mounted on a large wheel that is free to turn with negligible friction about a vertical axis. A toy train of mass m is placed on the track and, with the system initially at rest, the train's electrical power is turned on. The train reaches a steady speed of 0.176 m/s with respect to the track. What is the angular speed of the wheel if its mass is 1.97m and its radius is 0.584 m? (Treat the wheel as a hoop, and neglect the mass of the spokes and hub.) (Answer 0.101 rad/s) Ok so: Vt= .176 m/s mt= M m2= 1.97M r= 0.584m I2=m2r2 Xf= ? (X is angular velocity, subscript t for train and 2 for wheel) 2. Relevant equations L=IX=rmv Li=Lf Lt+L2=0 3. The attempt at a solution So I set it up with the initial equation Lt = -L2 rmtvt = IX Then expanded and substituted for corresponding masses rMv = 1.97Mr2X M cancels and so does an r, so vt = 1.97rX Then substitute the values .176 = 1.97(.584)(X) I get a final answer of X = .153 rad/s The answer is supposed to be .101 rad/s which I can't seem to get. Also I used X for angular speed instead of omega because the text formatting wasn't working, and about 4 different symbols showed up instead of omega. Not sure why.