posted by Sasha on .
calculate the force of Earth's gravity on a spacecraft 12,800 km (2 Earth radii) above Earth's surface if its mass is 1350 kg.
i know the universal gravitation formula is Fg = G [(m1 m2)/ r^2] but im not getting anywhere near the multiply choice answers of: 14,470, 4410 N, 2205 N, or 1470 N
r is the distance to the centre of the body. What did you use for r?
i tried squaring earth's radii and i tried multiplying it by 2
"(2 Earth radii) above Earth's surface" means 3 earth radii from the centre, right?
I have no clue