This is a problem I'm having a world of problem with: A. What is the angular momentum of a 2.56 kg uniform cylindrical grinding wheel of radius 17.5 cm when rotating at 1480 rpm? Correct: 6.08 kg*m^2/s B. How much torque is required to stop it in 6.50 s? So after 5 tries, I get that Torque = Moment of Inertia * Alpha. Alpha = Delta (w)/ Delta (t) Then I = 1/2*m*r^2 and I get .9347 N*m, but the computer does not. Any suggestions as to what I am doing wrong?