1. A Force Caused by Gravity

3.  If we apply Newton’s 2 nd Law to objects accelerating due to gravity F G = mg  F G – force of gravity, commonly called weight

4.  When an object is resting on the surface of Earth, the force of gravity is still acting, even though the object is not moving  Must be another force acting to balance the force of gravity, called the Contact Force  When the contact force acts perpendicular to the surface it is referred to as the Normal Force (F N )

5.  A 3.5kg box is resting on the floor. Draw the free body diagram

6.  A 10.0kg box is resting on a table a) draw the free body diagram b) now it is pushed down with a force of 40N. Draw the free body diagram. c) now it is pulled up with a force of 40N. Draw the free body diagram.

7.  What happens when the box in the previous problem is pulled up with a force of 100N?