Advertisements
Advertisements
प्रश्न
A block of wood of volume 25 cm3 floats in water with 20 cm3 of its volume immersed in water.
Calculate:
(1) density of wood
(2) the weight of block of wood.
Advertisements
उत्तर
Volume of wooden block = V = 25 cm3
Volume of wooden block immersed in water = 20 cm3
Volume of water displaced by wooden block=volume of wooden
block immersed in water = 20 cm3
Density of water = ρwater = 1 gcm-3
Density of wooden block =ρwood = ?
By law of floatation:
volume of wooden block x Density of wood=Volume of water displaced x Density of water
`25 xx rho_"wood" = 20 xx 1`
`rho_"wood" = 20/25 = 0.8` g cm-3
Weight of wooden block `"V"rho_"wood""g"`
= 25 × 0.8 × g = 20 gf
APPEARS IN
संबंधित प्रश्न
A solid iron ball of mass 500 g is dropped in mercury contained in a beaker. (a) Will the ball float or sink? Give reasons. (b) What will be the apparent weight of the ball?
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.
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.
A body floats in a liquid A of density ρ1 with a part of it submerged inside the liquid, while in liquid B of density ρ2 it is totally submerged inside the liquid. The densities ρ1 and ρ2 are related as :
A weather forecasting plastic balloon of volume 15 m3 contains hydrogen of density 0.09 kg m-3. The volume of equipment carried by the balloon is negligible compared to its own volume. The mass of an empty balloon alone is 7.15 kg. The balloon is floating in air of density of 1.3 kg m-3. Calculate:
(i) The mass of hydrogen in the balloon,
(ii) The mass of hydrogen and balloon,
(iii) The total mass of hydrogen, balloon and equipment if the mass of equipment is x kg,
(iv) The mass of air displaced by balloon and
(v) The mass of equipment using the law of floatation.
State the principle of floatation. What can you say about the average density of a ship floating on water?
Explain the following:
Icebergs floating in the sea are very dangerous for ships.
Why does a helium balloon float in air?
Name different types of Hydrometers with their applications.
