For a floating body, how is its weight related to the buoyant force?

It is easier to swim in sea water than in river water. Explain the reason.

The diagram given below shows a body floating in three different liquids A, B and C at different levels.

(a) In which liquid does the body experience the greatest buoyant force?

(b) Which liquid has the least density?

(c) Which liquid has the highest density?

Explain why an iron needle sinks in water, but a ship made of iron floats on water.