Sunday, March 1, 2015

Density

Density is the mass per unit volume of a substance. The symbol used for density is p (Greek letter rho) and its units are kg/m3

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where m is the mass in kg, V is the volume in m3 and p is the density in kg/m3

Some typical values of densities include:

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The relative density of a substance is the ratio of the density of the substance to the density of water, i.e.

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Relative density has no units, since it is the ratio of two similar quantities. Typical values of relative densities can be determined from above (since water has a density of 1000 kg/m3), and include:

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The relative density of a liquid may be measured using a hydrometer.

For example, the relative density of a piece of steel of density 7850 kg/m3 , given that the density of water is 1000 kg/m3 , is given by:

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