A boat floating in fresh water displaces water weighing 35.6 kN. (a) What is the weight of the water this boat displaces when floating in salt water of density 1.10 x 10^3 kg/m^3? (b) What is the difference between the volume of fresh water displaced and the volume of salt water displaced?

Answer 1

a) Hey, the boat weighs the same and must displace the same mass of water, fresh or salt, exactly 35.6 kN. Of course it must displace a greater volume of the less dense fresh water and therefore will float lower in the fresh water than in the salt water. The difference in volume will be in the ratio of the densities ( 1.1 / 1.0 ) in this case). By the way that is very salty salt water indeed.