Question

An object floats in water with half of its volume immersed in water. What will be its relative density?





Answer



When a body floats in water, the upthrust it experiences is equal to the weight of the body.

Hence, upthrust (U) = Weight of the body

U=mg

(Where,m= mass of the body andg= acceleration due to gravity)

Mass (m) = Density (d) × Volume (V)

Therefore,

U=d×V×g...(1)

Upthrust is also equal to the weight of water displaced.

Volume of water displaced is,Vbeing the volume of the object.

Therefore,

U= Mass of water displaced ×g

(whered w= density of water) ...(2)

Since the weight of the object is equal to the weight of the displaced water,





Therefore, the relative density of the object is.









































Q8)



How do the densities of solid, liquid and gas vary with temperature?





Answer



Solids:All forms of matter expand on heating; but in solids, heating has very little effect on the volume of the solid. As a result, the density of a solid does not change much with variation of temperature.

Liquids and Gases:When liquids and gases are heated, their volume increases. As volume is inversely proportional to density, an increase in volume, results in a decrease in density. Hence, with the increase in temperature, densities of liquids and gases decrease and vice versa.





































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Answer 1

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