1. The problem statement, all variables and given/known data A flywheel is attached on the output of the gearbox. The output shaft rotates in the opposite direction to the input shaft at 5 times its speed. The gearbox has an efficiency of 92%. If the flywheel is solid, has a mass of 50kg, a diameter of 1.5m and is to accelerate from rest to 300 revs min-1 in 1min: a) Calculate the torque required at input T1. 2. Relevant equations T=I*α I=0.5*m*r2 α=I(ω2-ω1)/t 3. The attempt at a solution Angular velocity of output shaft 300 revs min = 31.41593 rads/s (10π) Angular velocity of input shaft 60 revs min = 6.283 rads/s (2π) moment of inertia of flywheel = 0.5*50*0.75^2 =14.0625 Kg m^2 Change in angular momentum =I(ω2-ω1) =14.0625(10π-2π) =112π kg m^2 s Torque = change of angular momentum / time T=112π/60 =5.86Nm I have seen a similar thread but with a completely different method and answer. Any advice please?