A piece of iron sinks in water. But, why doesnt a ship made of iron sink in water?
Hi Sumukh!
Buoyant force is given as FB = Vρg, where V is the volume of displaced liquid, ρ is the density of water and g acceleration due to gravity. If the value of this force is greater than that of weight of the object, the object will float, otherwise it will sink.
A piece of iron may not displaces enough water to have a buoyant force which can keep it afloat, hence it sinks. A ship is designed in a way to displace enough volume of liquid so that the buoyant force can keep it afloat.
Hope it is clear!
Best wishes!!