Define relative density.Give its mathematical form

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floatation

#1

(i)Define relative density.Give its mathematical form.
(ii)The mass of an iron cube having an edge length 1.5 cm is 50 g. Find its density.
(iii)The volume of a 250 g sealed tin is 400 cubic cm. Find the density of the tin in g ${{cc}^{-1}}$. State, if the object would sink or ‘ float in water.


#2

(i) The relative density of a substance is the ratio of its density to that of water.
Relative velocity of substance = Density of substance / Density of Water
In other words, Relative density of substance = Mass of substance / Volume of the substance x Volume of water / Mass of water
(ii)Given that , mass of the cube = 50 g
Side of the cube = 1.5 cm
Volume of the cube = ${{1.5}^{3}}$ ${{cm}^{3}}$
Density = Mass / Volume = 50/ 3.375 = 14.81 ${{cm}^{-3}}$
(iii) Given that , mass ,m =250g
Volume,V = 400cc
Density = Mass / Volume = 250/400 = 0.625 g ${{cc}^{-1}}$
As we know that, density of water = 1 g ${{cc}^{-1}}$. So, density of tin is less than that of water and hence tin will float.