Hewitt-Drew-it! PHYSICS 21. Newton's Third Law

p83 #2: When a hammer exerts a force on a nail, how does the amount of force compare with that of the nail on the hammer?

#4: When swimming, you push the water backward - call this action. What is the reaction force?

#3: When you walk along a floor, what pushes you along?

#21: Consider two forces acting on a person who stands still, namely, the downward pull of gravity and the upward support of the floor. Are these forces equal and opposite?

• Yes

• No

21b. Do they comprise an action-reaction pair? Why or why not?

#29: If a bicycle and a massive truck have a head-on collision, upon which vehicle is the impact force greater? Which vehicle undergoes the greater change in its motion? Defend your answers.

#34: Your teacher challenges you and your best friend to each pull on a pair of scales attached to the ends of a horizontal rope, in tug-of-war fashion, so that the readings on the scales will differ. Can this be done? Explain.