A force is defined as:
A push or a pull that acts on an object due to the interaction with another object
Forces can affect bodies in a variety of ways:
Changes in speed: forces can cause bodies to speed up or slow down
Changes in direction: forces can cause bodies to change their direction of travel
Changes in shape: forces can cause bodies to stretch, compress, or deform
Resultant Forces on a Straight Line
A resultant force is a single force that describes all of the forces operating on a body
When many forces are applied to an object they can be combined (added) to produce one final force which describes the combined action of all of the forces
This single resultant force determines:
The direction in which the object will move as a result of all of the forces
The magnitude of the final force experienced by the object
The resultant force is sometimes called the net force
Forces can combine to produce
Balanced forces
Unbalanced forces
Balanced forces mean that the forces have combined in such a way that they cancel each other out and no resultant force acts on the body
For example, the weight of a book on a desk is balanced by the normal force of the desk
As a result, no resultant force is experienced by the book, the book and the table are equal and balanced
