1. The problem statement, all variables and given/known data I'm working through a practice test my professor has given us. The question is as follows: Two uniform solid cylinders, each with radius R and mass M are spinning about their individual axes, with angular velocity w1, each in a counterclockwise direction. They are brought together so they rub against each other and eventually they have stuck together at one point. They are now rotating about the point where they have stuck together with angular velocity w2. We are supposed to show that w2= 1/3 w1 2. Relevant equations His work looks like this: L1 = I1w1 + I1w1 = (1/2 MR^2 + 1/2 MR^2)w1 = MR^2 w1 L2 = 2 (3/2 MR^2) w2 = 3MR^2W2 3. The attempt at a solution My question is where is he getting L2 from? Where is 3/2 coming from, why is he multiplying by two, and is there an easier or more intuitive way of solving this problem other than his solution?