A diver is in inside of a coffin full of gold in the seabed. The coffin has a mass of 510kg and a volume of 0.26m3, so its density is 1961 kg/m3. The diver has a rubber balloon which is neutrally bouyant when it is empty and he wants to use it to take the coffin to the sea surface. The diver will fill the balloon at a depth of 50m.
a) Determine the minimum volume of air that the diver should add to the balloon so the coffin can start to float and move to the surface. Air weight in the balloon can be ignored.
b) What happens when the balloon start going up to the surface, taking into account that the balloon's walls are flexible?
c) Determine the buoyant force that acts on the balloon when it has go up to a depth of 10m (40meters from the seabed). Hint: Can assume that the air temperature doesn't change as it goes to the surface.