Advertisements
Advertisements
प्रश्न
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?
Give reasons.
Advertisements
उत्तर
(a) It will float with some part outside water.
Reason : On adding some salt to water, the density of water increases, so upthrust on a block of wood increases, and hence, the block rises up till the weight of salty water displaced by the submerged part of block becomes equal to the weight of the block.
(b) The block will sink.
Reason: On heating, the density of water decreases, so upthrust on the block decreases and the weight of block exceeds upthrust due to which it sinks.
APPEARS IN
संबंधित प्रश्न
State the principle of floatation.
A body of volume V and density ρs , floats with volume v inside a liquid of density ρL. Show that `"v"/V = ρ_s/ρ_L` .
A piece of ice floating in a glass of water melts, but the level of water in the glass does not change.
Give reasons.
Hint: Ice contracts on melting.
Explain the following :
Icebergs floating in sea are dangerous for ships.
A body of weight W is floating in a liquid. Its apparent weight will be
Why does a ship make of iron not sink in water, while an iron nail sinks in it?
Name an instrument based on this principle. State two uses of the instrument that you describe.
State the principle of floatation. What can you say about the average density of a ship floating on water?
Explain the following:
A hydrometer is made heavy near the bottom.
Why do petroleum-based products float on the surface of the water?
