Physics
posted by Rachel .
A 25 N book sits on a table. What is the magnitude of the normal force the table exerts on the book?

Hint: The acceleration of the book is zero. Therefore, the sum of all the forces that act on the book is zero.

Newton's 3 law:
For every action there is an equal and opposite reaction: ↑ N == mg↓
normal force N = mg = 25 N