The Concept of Force
We have an intuitive idea of what a "force" is. We may think of a force as a "push" or a "pull".
The direction of a force is important for force is a vector. (Recall my ancient joke(?) about the two friends trying to push a piano through the door -- one trying to push it into the apartment and the other trying to push it out of the apartment).
The net force on an object is the vector sum of all the forces on that object.
If the net force is non-zero an object's motion will change. We will see more of this with Newton's Second Law.
ToC Inertia Return to ToC, Ch4, Newton's Laws of Motion (c) 2002, Doug Davis; all rights reserved