Forces Act in Pairs 2.3 Outline

I. Newton’s third law relates action and reaction forces Newton’s third law: for every action there is an equal and opposite reaction example: a jellyfish applies a force down, the water pushes back

A. Action and Reaction Pairs action/reaction force pair is known as the force that is exerted on an object and the force that the object exerts back action and reaction forces do not always result in motion; for example if you press down on a table, the table pushes back with the same force, but there is no motion

B. Action and Reaction Forces Versus Balanced Forces balanced forces act on a single object example: if two friends pull on opposite sides of backpack with same force, no motion... BALANCED

B. Action and Reaction Forces Versus Balanced Forces (cont.) action/reaction forces act on different objects example: when dragging a heavy backpack, the backpack pulls back on you with equal and opposite force

II. Newton’s three laws describe and predict motion Newton’s three laws can explain the motion of almost any object the three laws are not independent of one another; they are used together to explain the motion of objects

II. Newton’s three laws describe and predict motion Newton’s laws can be used to make predictions about motion if you know the force acting on an object, then you can predict how that object’s motion will change