What does force mean?

A force is simply a push or a pull.

More specifically, a force causes objects to accelerate according to Newton's 2nd law: ##sumF = m*a##

F = Force (A Newton is the standard SI Unit) m = mass (A kg is the standard SI Unit) a = (A ##m/s^s## is the standard SI Unit)

According to physicsclassroom.com:

A force is a push or pull upon an object resulting from the object's interaction with another object. Whenever there is an interaction between two objects, there is a force upon each of the objects. When the interaction ceases, the two objects no longer experience the force. Forces only exist as a result of an interaction.

For simplicity sake, all forces (interactions) between objects can be placed into two broad categories:

• contact forces, and
• forces resulting from action-at-a-distance

For more, see: http://www.physicsclassroom.com/class/newtlaws/Lesson-2/The-Meaning-of-Force