Reading: Balanced/Unbalanced Forces

Balanced and Unbalanced Forces
A force is a push or a pull. Many different
forces act on objects around us all the time.
Balanced Forces
If the forces on the object are balanced,
then the object doesn’t move.
When two forces acting on an
object are equal in size, but
opposite in direction, we say the
forces are balanced. Balanced
forces do not cause a change in
motion. A book sitting on a table
demonstrates balanced forces.
Unbalanced Forces
When two or more forces are acting on an object
and they are not equal in size, we say the forces
are unbalanced. Unbalanced forces cause a
change in the motion of an object. An apple falling
from a tree demonstrates an unbalanced force.
If the forces on an object are
unbalanced, then the object will do one of
the following:
•Start moving
•Stop moving
•Change directions
•Slow down
•Speed up
Force Diagrams
We can show the forces acting on an object in a
force diagram. In a force diagram, the larger force
is shown with a bigger arrow, and the smaller force
is shown with a smaller arrow. The arrows also show
the direction the force is acting in. Force is
measured in Newtons, and some force diagrams will
label the force with the number of Newtons. Force
diagrams allow us to predict the direction and
movement of an object.
The most important thing to remember is moving objects
are unbalanced, objects that are not moving are balanced.