- #1
felipeek
- 4
- 0
Is it correct to write this:
[itex]\rho=\frac{dm}{dv}[/itex]
where [itex]\rho[/itex] is density, [itex]dm[/itex] is a differential of mass and [itex]dv[/itex] a differential of volume?
We know that [itex]\rho=\frac{m}{v}[/itex] when [itex]m/v[/itex] is constant. But, if density is not constant, or, in other words, [itex]m/v[/itex] changes, could we express the variation of [itex]m/v[/itex] as [itex]dm/dv[/itex] to calculate the density at one point?
I'm asking it because I've never seen density written in that way, however we can express mass as [itex]m=\int \rho dv[/itex]. Is there some physical mistake in the first expression?
Thanks!
[itex]\rho=\frac{dm}{dv}[/itex]
where [itex]\rho[/itex] is density, [itex]dm[/itex] is a differential of mass and [itex]dv[/itex] a differential of volume?
We know that [itex]\rho=\frac{m}{v}[/itex] when [itex]m/v[/itex] is constant. But, if density is not constant, or, in other words, [itex]m/v[/itex] changes, could we express the variation of [itex]m/v[/itex] as [itex]dm/dv[/itex] to calculate the density at one point?
I'm asking it because I've never seen density written in that way, however we can express mass as [itex]m=\int \rho dv[/itex]. Is there some physical mistake in the first expression?
Thanks!