There is a hydrogen balloon with a diameter of 150 ft. The mass of the balloon including the payload and hydrogen gas is 13 000 lbm. The balloon experiences a bouyancy force equal to Vpg, where V is the displaced volume, p is the air density and g = 32.17 ft s. (a) In a standard atmosphere, at what altitude would the balloon float? (b) Suppose the temperature dropped by 50 F while the pressure remained constant. What would be the new density altitude?