(1) Find the buoyant force acting on the He balloon. The volume of the balloon might be calculated from the following. The balloon has a shape of a sphere with the diameter of 10 m. You may also need the density of the gas in the balloon: rHe=0.166 g/L at Standard Temperature and Pressure (STP, 20oC, 1 atm) and of the air, rAir=1.205 g/L.
(2) Find the net lifting force, if all material of the balloon with two passengers has a mass of 190 kg.
(3) How many more mass may the balloon lift?