Newton's First Law States:

An object at rest will remain at rest until acted upon by some outside unbalanced force.
ALSO:
An object in motion will remain in motion at a constant speed in a straight line unless acted upon by some outside unbalanced force.

(Because a constant speed in a straight line is constant velocity, we can say that it stays in a constant state of motion. The object at rest, is also in a state of motion. It just happens to be not moving. And it will remain that way until there is an unbalance push.

Check out the .


We've also been analyzing free-body diagrams. This is a way of determining the total force on an object.

IT IS IMPORTANT TO NOTE THAT FREE-BODY DIAGRAMS DO NOT SHOW MOTION. THEY SHOW ACCELERATION. Only if there are frictional forces involved can you tell which direction the object is traveling, but you can always know how it is changing it's motion.

Here is a ppt on that.

Some free-body diagrams.