Question regarding newtons third law of motion I'm taking a module in physics, and I'm quite confused with applying Newton's third law of motion. I know in the following examples we are usually just interested in the forces acting on the book and the car, but to understand it I wanted to take a look at the big picture, so could you let me know if I have the basic idea.
Say you have a book resting on a table which is resting on the floor. You end up with four pairs of forces. 


*

*Force due to gravity on the book, equal and opposite one on the earth.

*A contact force on the table equal to the force due to gravity on the book, and a normal reaction force on the book equal and opposite to the contact force.
... then you have two more pairs: one between the desk and the earth and one between the floor and the desk. The force of the floor on the desk is equal and opposite to the contact force of the book on the table and the weight of the table.
so thats 1 problem. I'm not sure if I have the right idea, but hopefully one of you can help me out. And with the car:
1: tire pushes back on road, road pushes forward on car
2.friction pushes back on the car and forward on the road, easily overcome.
and I guess air resistance and other forces eventually bring the car to a contstant velocity.
 A: Newton's third law can be used to state that "The force due to the Earth on the table is equal and opposite to the force due to the table on the Earth"
But! The statement that the force is equal to the contact force of the table on the Earth plus the weight of the book is not necessarily true. In the above question, assuming that neither of the table or the book have an acceleration in the vertical direction, then it is true. 
Now coming to the "car" problem, (Its a nice one)
Consider a road with no friction, and the wheel rotates clockwise. Now look at the bottom most point of the wheel (The point which is in contact with the road)(In my diagram it is point 'P'). The point appears to move backwards.

Now, just add in some friction. 
Now friction has just one protocol "OPPOSE RELATIVE MOTION!"
So in other words, when you add in friction between the tire and the road, friction sees that the point which is experiencing friction (Point P) is moving backwards, So it gives a force in the forward direction. Now you can extend this argument by saying that "Using Newton's third law, since the forces will act in opposite pairs, The friction on the ground due to the tire is in the backward direction". And that's completely true! (( Ofcourse we dont see the ground moving back :p ))
So to summarize, Friction acts in the forward direction for the tire.
