- #1
enc08
- 42
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Hi,
I'm trying to understand the mass conservation equation for a pulsating sphere which has thickness dr. Please refer to the attached solution.
[tex]\rho = \rho_{0} (ambient density) + \rho' (small deviation)[/tex]
There are two things I don't follow.
First, is that to obtain the mass, the area of the sphere is multiplied by the speed (and density) at which it is pulsating. Although the units work out, I don't see the physical meaning behind taking the product with speed .
Secondly, on the LHS, the ρ turns into a ρ'. I can't see how this substitution was made.
Thanks for your input!
I'm trying to understand the mass conservation equation for a pulsating sphere which has thickness dr. Please refer to the attached solution.
[tex]\rho = \rho_{0} (ambient density) + \rho' (small deviation)[/tex]
There are two things I don't follow.
First, is that to obtain the mass, the area of the sphere is multiplied by the speed (and density) at which it is pulsating. Although the units work out, I don't see the physical meaning behind taking the product with speed .
Secondly, on the LHS, the ρ turns into a ρ'. I can't see how this substitution was made.
Thanks for your input!