Posted by Andy on .
The mass of Venus is 0.8140 times that of earth, and its radius is 0.950 times that of earth. Calculate the acceleration of gravity at the surface of Venus. Express your answer in g's (i.e. as a ratio to our acceleration of gravity).
9.01×101 is the correct ratio
Calculate the average density of Venus (in kg/m3) given the earth's density is 5.52×103 kg/m3.
this is the part I'm having trouble with.
Any help would be greatly appreciated thanks!

Physics 
MathMate,
The general gravitational attraction formula is
F = GMm/r²
from which g= F/m = GM/r²
To find the value of acceleration on Venus relative to the value on earth, we have
g*0.8140/(0.95)²
=0.9g
Density = mass / volume
Since volume of a sphere is proportional to the cube of the radius
Density = mass / volume
=mass /((4/3)πr³)
Let the average density of earth be
ρ=5.52*10³ kg/m²
density on venus (by proportions)
=ρ*0.8140/0.95³
=0.95ρ approx.