physics
posted by Melissa on .
The force of gravity at Earth's surface on an astronaut is 634N. What is the force of gravity on the same person at each of the following distances, in multiples of Earth's radius, from the centre of Earth?
A)2 B)5 C)10 D)17.2

Hmmmm. I am not certain how the force of gravity can ever be greater on an astronaut at multiples of earth radii. It gets smaller as one goes out.

If
mg = GmM/R^2 = 634 N,
then I believe that
(mg)1 = GmM/(2R)^2 = 634/4 =158.2 N
(mg)2 =634/25 =25.36 N
(mg)3 =634/100= 6.34 N
(mg)4 =634/(17.2)^2 = 2.14 N
All changes are due to the changes in "g".