Physics
An iron nail sinks in water while an iron ship floats on water. Explain the reason.
Answer
An iron nail sinks in water because the density of iron is greater than the density of water, so the weight of the nail is more than the upthrust of water on it.
On the other hand, the ship is hollow and the empty space in it contains air which makes it volume large and average density less than that of water. Therefore, even with a small portion of ship submerged in water, the weight of water displaced by the submerged part of ship becomes equal to the total weight of ship and therefore, it floats.
Related Questions
A man first swims in sea water and then in river water.
(i) Compare the weights of sea water and river water displaced by him.
(ii) Where does he find it easier to swim and why?
A loaded cargo ship sails from sea water to river water. State and explain your observation.
A block of wood is so loaded that it just floats in water at room temperature. What change will occur in the state of floatation, if
(a) some salt is added to water,
(b) water is heated?
Why is floating ice less submerged in brine than in water?