Download M m FGR = M m FGR = 1 1.9 0.72 0.72 M m GFRRRM m FRRGR

The radius of Venus’ orbit is 0.72 times that of the Earth’s orbit. How much stronger is the Sun’s gravitational field at Venus than at Earth? Though it seems like the question is asking about the gravitational force on Earth and on Venus, it is actually asking at the force on a generic mass located at the two distances from the Sun corresponding to each planet’s orbit. The drawing shows the nearly circular orbits of Venus and the Earth. If we had an object of mass m located at the distance RV from the Sun, the gravitational force on it would be: FV  G
RV MSun m RV2
If the same mass is located at the distance RE from the Sun, then the Sun’s gravitational force on it is: FE  G
MSun m RE2
Now, let’s take the ratio of these two forces to answer the question. MSun m
FV
RV2
RE2
RE2
1




 1.9
MSun m RV2  0.72R 2  0.72  2
FE
E
G
RE2
G
RE