1. The problem statement, all variables and given/known data A merry-go-round has a mass of 1440kg and a radius of 7.50m . How much net work is required to accelerate it from rest to a rotation rate of 1.00 revolution per 7.00s? Assume it is a solid cylinder. 2. Relevant equations I believe my relevant equations are: ICYL=½mr2 ω=(Δθ/Δt) α=(Δω/Δt) tau=Iα (moment of inertia * alpha) W=tau*Δθ 3. The attempt at a solution First I calculated the moment of inertia as: ICYL=½(1440kg)(7.50m)2=40500 kg⋅m2 Then I calculated ω as 2π/7.00s Knowing ω allowed me to calculate α as: (2π/7.00s)/7.00s=2π/49.00s2 Then I used the tau equation to calculate tau as Iα=(40500 kg⋅m2)*(2π/49.00s2)=5193.244999J Then I used the work equation to calculate work as tau*Δθ=5193.244999J*2π=32630.12067J With 3 sig figs, this would be 3.26*104J The problem is, the book says the answer is 1.63*104J and I can't figure out why.