1. Below is a collection of statements explaining Newton's second law of motion in words similar to those often presented in high school and college textbooks.
FOR TODAY’S QOD, YOU AND YOUR PARTNER, WILL COME UP WITH YOUR OWN STATEMENT EXPLAINING NEWTON’S 2nd LAW. Do this on the BIG whiteboards.

2. “FOR EVERY ACTION THERE IS AN EQUAL AND OPPOSITE REACTION”3
“FOR EVERY ACTION THERE IS AN EQUAL AND OPPOSITE REACTION”

4. “FOR EVERY ACTION THERE IS AN EQUAL AND OPPOSITE REACTION”
Newton’s 3rd Law
“FOR EVERY ACTION THERE IS AN EQUAL AND OPPOSITE REACTION”
Book to
earth
Table to
book

5. THINK ABOUT IT . . .
What happens if you are standing on a skateboard or a slippery floor and push against a wall? You slide in the opposite direction (away from the wall), because you pushed on the wall but the wall pushed back on you with equal and opposite force.
Why does it hurt so much when you stub your toe? When your toe exerts a force on a rock, the rock exerts an equal force back on your toe. The harder you hit your toe against it, the more force the rock exerts back on your toe (and the more your toe hurts).

6. A force is a push or a pull upon an object which results from its interaction with another object.
According to Newton, whenever objects A and B interact, they exert forces upon each other.
When you sit in your chair, your body exerts a downward force on the chair and the chair exerts an upward force on your body. There are two forces resulting from this interaction - a force on the chair
a force on your body.
These two forces are called action and reaction forces and are the subject of Newton's third law of motion.

7. ACTION AND REACTION ON DIFFERENT MASSES
CONSIDER: you and the earth
ACTION: earth pulls on you
REACTION: you pull on earth

8. THE WHEELS ON THE BUS ACTION: tire pushes on road
REACTION: road pushes on tire

9. LOST in SPACE Reaction: gases push on rocket
Action: rocket pushes on gases

10. Consider the motion of a car on the way to school
Consider the motion of a car on the way to school. A car is equipped with wheels which spin backwards. As the wheels spin backwards, they grip the road and push the road backwards.
In turn, the road reacts by
pushing the wheels forward.
For every action, there is an equal (in size) and opposite (in direction) reaction.
Action-reaction force pairs make it possible for cars to move along a roadway surface.

11. Consider hitting a baseball with a bat
Consider hitting a baseball with a bat. If we call the force applied to the ball by the bat the action force, identify the reaction force.
(a) the force applied to the bat by the hands
(b) the force applied to the bat by the ball
(c) the force the ball carries with it in flight
(d) the centrifugal force in the swing

12. Consider the flying motion of birds. A bird flies by use of its wings
Consider the flying motion of birds. A bird flies by use of its wings. The wings of a bird push air downwards. In turn, the air reacts by pushing the bird upwards.
The size of the force on the air equals the size of the force on the bird; the direction of the force on the air (downwards) is opposite the direction of the force on the bird (upwards).
For every action, there is an equal (in size) and opposite (in direction) reaction. Action-reaction force pairs make it possible for birds to fly.
air reacts
by pushing
the bird upwards
wings of a bird push
air downwards

14. Problem #1
A horse pulls forward on a carriage with a given force. By Newton's Third Law, the carriage must be pulling on the horse backward with an equal and opposite force. Given this, what explains why the horse and carriage can move forward?

15. Problem #2
You and a friend are pulling on a rope in opposite directions as hard as you can. What is the "equal and opposite force" to the force of your hand pulling on the rope described by Newton's Third Law?

16. Problem #3
Which best explains why we are able to accelerate forward when starting to run?