Earth and Sun - Gravity problem

AI Thread Summary
The discussion centers on calculating the Sun's mass and comparing its density to Earth's. The Sun's mass is determined to be approximately 2.0 x 10^30 kg, while its density is found to be one-fourth that of Earth's density. The gravitational force equations are referenced, but there is confusion about applying them correctly to find the answers. Participants express uncertainty about how to approach the density comparison based on the radii of the Sun and Earth. The conversation highlights the need for clarity in using gravitational equations and understanding density calculations.
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Homework Statement


Earth is a satellite of the sun with an orbit radius of approximately 1.5 x 10^11 m.

a) What is the Sun's mass? **Answer:** 2.0 x 10^30 kg

b) If the Sun's radius is 6.96 x 10^8 m, how does the Sun's density compare with Earth's density? **Answer:** Psun = 1/4 Pearth

Homework Equations



g = G*m/r^2 and Fg = G*m1*m2/r^2

The Attempt at a Solution



a) So G*m1*m2/r^2

G*(m of the earth)*(mass of the sun)/radius^2

I put these values in but didn't get the answer?

b) I don't know how to do this one? Would I just see what fraction of the Sun's radius is the Earth's and that's similar to the density?
 
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