Newton's First Law and Balanced Forces

Your study of balanced forces and Newton’s First Law should have provided you with an understanding of how to recognize situations involving balanced forces and how to calculate unknown forces when forces are balanced. You should have learned that inertia is a property of matter that resists changes in motion.  Inertia is what keeps moving objects moving and what allows objects at rest to remain at rest. Newton’s First Law of Motion shows how inertia is maintained by balanced forces so that objects with balanced forces have constant motion. If you know that the net force on an object is zero, you can often use that knowledge to deduce the value of unknown forces by setting the up/down and left/right forces equal to each other. One force that you often deal with is friction, which you can calculate by multiplying the normal force by the coefficient of friction, which is specific to every pair of material surfaces.

For more information on Newton's First Law view the video clip Newton's Laws of Motion from Discovery Education™ streaming.