A restatement of Newton's third law started the class. Examples of action forces were presented and Abby was requested to name the reaction force for each. The single, underlying force of friction was indicated as the reaction force in many cases. Problems involving the free fall of a rock (action force) with the reaction force being the rocks attraction to the Earth. Why we don't "feel" the Earth moving toward the rock was presented, using the second law equation to answer the question. The usual example of a cannon and cannonball was also presented.
Assig. # 8 given