1. The problem statement, all variables and given/known data A thin, light wire is wrapped around the rim of a wheel,. The wheel rotates without friction about a stationary horizontal axis that passes through the center of the wheel. The wheel is a uniform disk with radius R = .280m. An object of mass m=4.2kg is suspended from the free end of the wire. The system is released from rest and the suspended object descends with constant acceleration. If the suspended object moves downward a distance of 3m in 2s what is the mass of the wheel? 2. Relevant equations Idisk = 1/2mr^2 τ=Iα αr=a 1/2at^2=x 3. The attempt at a solution First I figured out the acceleration of the block with 1/2at^2=x. With x = 3 and t = 2 you get a=6/4. Then i set up τ=Iα=1/2*mw*r^2*(a/r)=mb*g*r (mb = mass bock and mw = mass wheel, i also substituted a/r for α. This equation reduces to 1/2*mw*a = mb*g with a = 6/4 we get 6/8*mw = mb*g mb is given at 4.2 so mw equals 55kg which is wrong. What am I doing wrong? The answer key has them giving the answer using energy equations which is all fine and good, but i'm confused why this isn't working.