Question

use newton's first law to explain why a book on a desk does not move.

Answer 1

From Google:

You can rewrite this anyway you wish.

Newton's first law states that, if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force. This postulate is known as the law of inertia.