A Single cylinder double acting steam engine develops 150 kw at a mean speed of 80 rpm. The co-efficient of fluctuation of energy is 0.1 and fluctuation of speed is 2% of the mean speed. If the diameter of the flywheel rim is 2 meters and the hub and spokes provided 5% of the rotational inertia of the flywheel. Find the mass and cross sectional area of the flywheel rim. Assume density of flywheel as 7200 kg/m3.