Submarines control how much they float or sink in the ocean by changing the volume of air and water contained
in large ballast tanks. When the tanks are completely full of water, the submarine increases its overall mass and
sinks down to the bottom. When the tanks are completely full of air, the submarine reduces its overall mass and
floats to the surface. Depending on the density of the seawater surrounding the submarine, it will pump
seawater in or out of the tanks in order to achieve the same overall density as the sea water and float neutrally
in the water
The volume of the submarine never changes. When the tanks are completely full of air, a submarine with a
volume of 2 x 10 m has a total mass of 1.5 x 105 kg. The density of the seawater is 103 kg/m".
To make that submarine float neutrally, and neither float nor sink in the ocean, what volume of water does that
submarine need to add to its tanks? (Ignore the mass of the replaced air.)