1. The problem statement, all variables and given/known data A wheel spins at 45rpm with its spin axis vertical. After spinning 15 sec, it is spinning at 60rpm with its axis horizontal. Find its average angular acceleration and the angle the avg acceleration vector makes with the horizontal. 2. Relevant equations Sorry, I can't really do the latex stuff, or whatever it's called. Avg Angular Accel = Delta Omega over Delta t 3. The attempt at a solution They're really easy numbers... I just converted rpms into rads/s for both so I got 3pi/2 rad/s for 45rpm and 2pi rad/s for 60rpm Then I did pi/2 divided by 15 seconds for pi/30 rad/s2 And of course my answer doesn't match up. I also said that the vector would be parallel to the horizontal, since it should be parallel with the angular velocity vector. The only main variable in the problem is the change of axis of rotation. Would that affect the number and angle I'm supposed to get? How do I figure that out if it does...? I thought this was a simple problem...but maybe not Please and thanks.