Hey. I'm studying Kleppner's book and I have a few questions about the example 2.3. Astronauts' Tug-of-War. It's said that "The negative sign means that aB is to the left", but in the diagram represents aB to the right... Why is this happening? Or are we talking about different situations? In fact, aA and aB should have opposite directions, which doesn't fit with our diagram... Can someone clarify this, please?