13-4 A man has a mass of 80 kg. In pure water, he floats fully submerged. (a) When he is in the air, what is the buoyant force on him due to the atmosphere? (Use the tabulated densities at 0 C.) (b) When he is submerged in sea water, "what is the buoyant force on him due to the water? Air density is 1.29 kg/m3 , Fresh water density is 1000kg/m and Sea water density is 1025kg/m3