The earth exerts a downward force of 850 N on a veteran astronaut as he works outside the space shuttle. What force (if any) does the astronaut exert on the earth?

Answer 1

Don't forces always have equal and opposite forces? Newtons third law says something about that.

When you stand on a scale, and it reads 100 lbs. Turn it upside down, let the Earth read its weight: 100 lbs, in the opposite direction.