Balance forces are two forces acting in opposite directions on an object and equal in size. Anytime there is a balanced force on an object, the object stays still or continues to move at the same speed and in the same direction. It is important to note that an object can be in motion even if no forces are acting on it.

Balanced forces can be demonstrated in hanging, floating, and standing or sitting objects.

Hanging objects

Take a look at this hanging glass bulb shade. The weight of the bulb shade pulls down, and the tension in the cable pulls up. The forces pulling down and pulling up can be said to be in balance.

Floating objects

Take a look at this log floating in a pool of water. It is floating because the weight of the log is balanced by the upthrust from the water. If more weight is tied to the log, the force pulling it down maybe more and will cause it to sink.

Standing/Sitting on a surface

Consider a metal block resting on a surface of a table. Its weight is balanced by the reaction force from the surface. The surface pushes up against the metal block, balancing out the weight (force) of the metal block.