Your 2.85kg physics book rests on a horizontal tabletop.

A. Find the normal force on the book.
B. Suppose you pull up on the book with a 15.0N force, now what's the normal force?
C. Suppose you push down on the book 15.0N Force now what's the normal force?

1 answer

A) m=2.85 kg, F=?, a=9.8 m/s^2 due to gravity.

F=m*a

F=2.85*9.8=27.9 N

B) Pulling up creates a force against the forces working so.. n-15N.
27.9N-15N=12.9N

C)Pushing up creates a force with the forces already working so.. n+15N
27.9N+15N=42.9N