The mass of a robot is 6930 kg. This robot weighs 2520 N more on planet A than it does on planet B. Both planets have the same radius of 3.01 × 106 m. What is the difference MA - MB in the masses of these planets?

Answer 1

FB = G MB 6930/(9*10^12)
MA 6930/(9*10^12)

MA = (9*10^12/6930 G) FA
MB = (9*10^12/6930 G) FB
----------------------------
MA - MB = (9*10^12/6930 G)(FA-FB)

Answer 2

Damon, I honestly want to thank you for your precious efforts in helping students.
I have a question regarding the equations you've set above. Could you clarify how to find FB please?

Answer 3

Gravitational force = G mplanet m/d^2
G = 6.67384 × 10-11 m3 kg-1 s-2
so
FB = 6.67384 × 10-11 m3 kg-1 s-2 MB*6930/(3.01*10^6)^2