density is simly mass per unit volume of a body,where as specific weight is the weight per unit volume of a body. So, specific weight has a “g” term associated with it.
Since weight is a force, scientists also write the equation as F = mg. F = symbol for weight, measured in Newtons, N. m = symbol for mass, measured in kilograms, or kg. g = symbol for gravitational acceleration, expressed as m/s2, or meters per second squared. If you're using meters, the gravitational acceleration at the earth's surface is 9.8 m/s 2. ...
γ (specific weight) = w (ordinary weight) / V (volume of the substance), or what is the same: ...
The SI unit for the specific weight is N/m 3 while the English unit is lb/ft 3. Specific gravity is simply the ratio of the specific weight of a given liquid to the specific weight of water at 4° C (γ water = 9.81 kN/m 3 or 62.4 lb/ft 3 ). This definition is helpful when comparing densities of different liquids.
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