What's the simplest way to determine the mass of a sphere from a plot of its density varying in r?

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Hey there,
So, within the context of a spherical body, I've got a plot of density varying in r which is generated through PDE solver. What would the neatest way of calculating the sphere's mass, based on said density plot, be?
Much appreciated.

Accepted Answer

Torsten on 28 Nov 2022
If r and rho are column vectors where r is ordered as r(1) < r(2) < ... < r(n) and rho is the density at position r, an approximation for the mass m of the sphere is
m = trapz(r,4*pi*r.^2.*rho)

More Answers (1)

William Rose
William Rose on 28 Nov 2022
I agree with @David Hill, except you want to multiply the density at each value of r by 4*pi*r^2*dr, then add them up, i.e. integrate. Because 4*pi*r^2*dr is the volume of each shell.


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