Just a little background before I present my question - I am a Psychology graduate looking to move into Neuroscience so I'm going through some Physics to learn more about this topic as it is relevant for some Neuroscience courses. As such I lack some background knowledge of Physics and have last studied it at GCSE about 5 years ago, so forgive me if my question is a little basic!
I'm going through a section on Newton's Laws at the moment and my textbook gives an example of a Newton Pair, identifying the gravitational pull of a person on the Earth and the contact force of the person on the Earth as the Newton Pair. Right underneath it says that to help identify Newton Pairs, you should remember they have to be the same type, e.g. both gravitational forces.
In the above example, it does not seem that the forces are the same type, but I have seen other similar examples, so feel I am missing something. I'd really appreciate it if somebody could explain this to me a little better, including why those two are a Newton Pair if they are different types of force and what I am missing in this example.