2.- A man of 73 kg has a volume of 75 l, of which 5 l correspond to the lungs. (a) Calculate the volume of the lungs when going in apnea underwater to a depth of 10 m, assuming that the density of sea water is 103 kg/m3 . (b) At that depth, will the total forces acting on him make him sink or will he be pushed towards the surface?