Advertisements
Advertisements
Question
Advertisements
Solution
We can find the relative density of a solid which floats on water by following the experiment.
Measuring the relative density of a cork
Choose a sinker and find its weight in water by suspending it in water.
Tie the solid to the string attached to the sinker and find its weight in air but sinker in water.
Remove the solid and tie it together with the sinker and suspend it in water and find the weight of the solid together with the sinker in water.
Record your observation as shown below:
Weight of sinker in water = x gf
Weight of sinker in water + solid in air = y gf
Weight of solid in air = (y - x) gf
Weight of solid + sinker in water = z gf
upthrust on solid in water = (y - z) gf.
The upthrust on in water also represents the weight of the water displaced by the solid. Relative density of solid = (weight of cork in air )/(weight of equal volume of water) Relative density = (y - x)/(y - z).
APPEARS IN
RELATED QUESTIONS
When a piece of wood is suspended from the hook of a spring balance, it reads 70 gf. The wood is now lowered into water. What reading do you expect on the scale of spring balance?
Draw a diagram to show the forces acting on a body floating in water with its some part submerged. Name the forces and show their points of application. How is the weight of water displaced by the floating body related to the weight of the body itself?
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 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 test tube loaded with lead shots, weighs 150 gf and floats upto the mark X in water. The test tube is then made to float in alcohol. It is found that 27 gf of lead shots have to be removed, so as to float it to level X. Find R.D. of alcohol.
Why does a ship make of iron not sink in water, while an iron nail sinks in it?
A rubber ball floats in water with 2/7 of its volume above the surface of the water. Calculate the average relative density of the rubber ball.
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.
Explain the following:
A hydrometer is made heavy near the bottom.
Differentiate positive & negative buoyant.
