posted by olga .
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?
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.