Advertisements
Advertisements
Question
A piece of wood of uniform cross section and height 15 cm floats vertically with its height 10 cm in water and 12 cm in spirit. Find the densities of wood and spirit.
Advertisements
Solution
Let densities of water, wood and spirit are ρ, ρw and ρs respectively.
Let A be the area of the wooden block.
Total volume of the wooden block is, V = 15A
1. Mass of wood = Mass of water displaced by the wood
Vρwg = A×10×ρ×g
ρw = `(A xx 10 xx ρ xx "g")/(15 xx A xx "g") = 0.67` g/cm3
2. Mass of the wood = Mass of then spirit displaced
Vρwg = A×12×ρs×g
ρs = 0.83 g/cm3
APPEARS IN
RELATED QUESTIONS
Assuming the density of air to be 1.295 kg m-3, find the fall in barometric height in mm of Hg at a height of 107 m above the sea level. Take density of mercury = 13.6 × 103 kg m-3.
A bunch of feathers and a stone of the same mass are released simultaneously in air. Which will fall faster and why? How will your observation be different if they are released simultaneously in vacuum?
A body of density ρ sinks in a liquid of density ρL. The densities ρ and ρL are related as :
A body weighs W gf in air and W1 gf when it is completely immersed in water. Find: (i) Volume of the body, (ii) Upthrust on the body and (iii) Relative density of the material of the body.
Calculate the mass of air in a room of dimensions 4.5 m × 3.5 m × 2.5 m if the density of air at N.T.P. is 1.3 kgm-3 .
Explain the following :
A balloon filled with hydrogen rises to a certain height and then stops rising further.
A block of wood of mass 24 kg floats on water. The volume of wood is 0.032 m3. Find:
- the volume of block below the surface of water,
- the density of wood.
(Density of water = 1000 kg m−3)
A wooden block floats in water with two-third of its volume submerged.
(a) Calculate the density of wood.
(b) When the same block is placed in oil, three-quarters of its volume is immersed in oil. Calculate the density of oil.
Select the correct option:
With the increase in the density of the fluid, the upthrust experienced by a body immersed in it:
Complete the following result:
Density in kg m-3 = ______ x density in g cm-3
