Physics
posted by Kyle .
Calculate the force of gravity on a spacecraft 19200 km (3 earth radii) above the Earth's surface if its mass is 1600 kg.
I've done all the work but I can't seem to get the right answer, please show work and answer.

No, I am not going to show all work. Goodness.
the force of gravity at Earth is mg
at 3 earth radii above, that is a total of 4 earth radii from then center, so weight at that altitude is 1/16 of mg.