Advertisements
Advertisements
प्रश्न
A solid body weighs 2.10 N. in air. Its relative density is 8.4. How much will the body weigh if placed
(1) in water,
(2) in liquid of relative density 1.2?
Advertisements
उत्तर
Weight of solid body in air = 2.10 N
R.D. of solid = 8.4
R.D. of solid = `("Density of solid"(rho_"solid"))/"Density of water"`
`8.4 = rho_"solid"/rho_"water"`
`rho_"solid" = 8.4 xx rho_"water" = 8.4 xx 1000 = 8400` kgm-3
(1) R.D. of solid = `"Weight of solid in air"/"Weight of water displaced by body"`
`8.4 = 2.10/"Weight of water displaced by body"`
Weight of water displaced by body = `2.10/8.4 = 0.25` N
Weight of body in water = Weight of body in air – Weight of water displaced by body
= 2.10 - 0.25 = 1.85 N
(2) Upthrust due to water = Weight of water displaced by body
= 0.25 N
Upthrust due to liquid = Upthrust due to water ×R.D. of liquid
= 0.25 x 1.2 = 0.30 N
Weight of body in liquid = Weight of body in air – Upthrust due to liquid
= 2.10-0.30= 1.80 N
APPEARS IN
संबंधित प्रश्न
A body dipped into a liquid experiences an upthrust. State two factors on which upthrust on the body depends.
A body held completely immersed inside a liquid experiences two forces:
(i) F1, the force due to gravity and
(ii) F2, the buoyant force.
Draw a diagram showing the direction of these forces acting on the body and state the condition when the body will float or sink.
Define the term density.
Express the relationship between the C.G.S. and S.I. units of density.
A piece of iron weighs 44.5 gf in air. If the density of iron is 8.9 × 103, find the weight of iron piece when immersed in water.
How does the density ρs of a substance determine whether a solid piece of that substance will float or sink in a given liquid ρL?
A body floats in a liquid with a part of it submerged inside the liquid. Is the weight of floating body greater than, equal to or less than the upthrust?
An inflated balloon is placed inside a big glass jar which is connected to an evacuating pump. What will you observe when the evacuating pump starts working? Give a reason for your answer.
A wooden cube of side 10 cm has a mass of 700 g. It will float in the water with:
(a) Half of its volume inside the water
(b) 3 cm height above the water surface
(c) 7 cm height above the water surface
(d) Just inside the water surface.
Complete the following result:
Mass = _______ × density
