1. The problem statement, all variables and given/known data This problem from Applied mechanics J Hannah M J Hilier An engine flywheel consist essentially of a ring of cast iron of density 7200 kg/ m3 .The flywheel has to deal with a fluctuation of energy of 22500 J at mean speed of 6 rev/s with a limit of +- 0,5 per cent on variation in speed .The maximum centrifugal stress in flywheel is not to exceed 5.5 MN/m2 .Find mean diameter and cross-sectional area of the rim . answers Deameter mean=1464 mm area =0.089 m2 2. Relevant equations greatest fluctuation of energy=IaW2 3. The attempt at a solution stress=density *[angular velocity]square * [radius mean]square