I've spent at least an hour trying to figure this out, but can't seem to figure out how to solve this. 1. The problem statement, all variables and given/known data A 170g , 30.0-cm-diameter turntable rotates on frictionless bearings at 66.0rpm . A 25.0g block sits at the center of the turntable. A compressed spring shoots the block radically outward along a frictionless groove in the surface of the turntable. What is the turntable's rotation angular velocity when the block reaches the outer edge? 2. Relevant equations Conservation of momentum: Ii*wi = If*wf 3. The attempt at a solution I(turntable) = Mr^2 = (.170 kg)(.15 m)^2 = 3.825*10^-3 kg m^2 I(block)o = mr^2 = 0 I(block)f = mr^2 = (.025 kg)(.15 m)^2 = 5.265*10^-4 kg m^2 wi = ((66 rpm)(2pi))/60 = 6.91 rad/s I(turntable+block)f = 3.825*10^-3 + 5.265*10^-4 = 4.3875*10^-3 kg m^2 (3.825*10^-3)(6.91) = (4.3875*10^-3)wf 0.1826 = (4.3875*10^-3)wf wf = 6.02 rad/s -- wrong Initially, I tried using conservation of energy, and ended up with 5.52 rad/s. The program told me "not quite" and suggested a rounding error, so I think 5.52 might be close to the right answer, but I can't seem to figure out why I'm not getting it. Any help would be much appreciated!