a physics book is on top of a drafting table at 35 degree angle. Find the net external force acting on the book and determing wether the book move or remain at rest on this position. they give you:

Question

a physics book is on top of a drafting table at 35 degree angle. Find the net external force acting on the book and determing wether the book move or remain at rest on this position. they give you:
force of friction 11N, force normal 18N,force of gravity on the book 22N.

Henry · Answer

The book will remain at rest if: F -Fg -Ff = 0 = Fn, F - 22 - 11 = 0, F = 22 + 11 = 33N