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Smartguy94
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Homework Statement
The density of a certain planet varies with radial distance as:
ρ (r)= ρo(1- αr/Ro)
where Ro= 3.98 x 106 m is the radius of the planet, ρo= 4980 kg/m3 is its central density, and α = 0.17. What is the total mass of this planet ?
Calculate the weight of a one kilogram mass located on the surface of this planet.
Homework Equations
ρ = m/v
The Attempt at a Solution
since ρ= m/v
then
m = ρv
v of a planet = 4/3∏ R^3
so i substitute the given info on the equations and got
m = ρo(1- αr/Ro) * 4/3∏ R^3
calculate all of those and I realize that i don't know what r is.
so I assume that r = Ro but I got the wrong answer
any help?