A book rests on the surface of the table. Consider the following four forces that arise in this situation:
(a) The force of the Earth pulling on the book,
(b) The force of the table pushing on the book,
(c) The force of the book pushing on the table,
(d) The force of the book pulling on the Earth.
The book is not moving. Which pair of forces must be equal in magnitude and opposite in direction even though they are not an interaction pair?