Fa The volume of the balloon, 4 Vol = =my3 Since the balloon is going upward steadily, the vertical force is in equilibrium, IF, = 0 -Fa + Fo - msg = 0 Fa = Fb - msg Pair VzCaA = (Pair - Phydrogen)9(Vol) - msg where, The Reynolds number, -PVD Re = and we can get the drag coefficient from the graph. Use trial and error method to find the corresponding Reynolds number and Velocity. Try another question like this one100 10 Circular disk - Drag coefficient C. 0.1 Sphere - 0.01 10 100 1,000 10,000 100,000 1,000,000 10,000,000 Reynolds number Re = U div A spherical weather balloon of 2 m diameter is filled with hydrogen. The total mass of the balloon skin and the instruments it carries is 3.7 kg. At a certain altitude the density of air is 1.0 kg/m and is 10 times the density of hydrogen in the balloon; the viscosity of air is 1.8x10" Ns/m . Determine the steady upward velocity of the balloon. m/s Check