1. Isaac Newton explained this relationship between force and the motion of an object.

2. Law of Inertia
Inertia is the tendency of an object to resist being moved or, if the object is moving, to resist a change in speed or direction until an outside force acts on the object.

3. Law of Inertia
Because of Inertia, an object at rest will stay at rest unless acted on by an unbalanced force.
In other words, objects will not start moving until a push or a pull is exerted on them.

4. Law of Inertia

5. Law of Inertia
An object in motion will remain in motion unless acted on by an unbalanced force.
The object will continue to move in the same direction with the same speed unless an unbalanced force occurs.

7. Mass and Inertia Mass is a measure of Inertia
An object that has a small mass has less inertia than an object that has a large mass
Changing the motion of an object that has a small mass is easier than changing the motion of an object that has a large mass.

8. The car because it has more mass therefore more inertia.
Mass and Inertia
Look at the images below. Which would require more force to move or slow down? Why?
The car because it has more mass therefore more inertia.

9. Mass and Inertia
Which would require more force to move or slow down? Why?
The bowling ball because it has more mass therefore more inertia.

10. The snowboard is in motion
The snowboard is in motion. Based on the Law of Inertia, the snowboard will keep moving right? What force(s) allow him to snowboard on the brick wall and rail?

11. Newtons’s 1st Law of Motion Friction and the Law of Inertia
Objects in motion remain in motion unless acted on by an unbalanced force. Friction is often the unbalanced force that causes objects to slow down and stop moving.
Because of friction, the motion of objects changes.

12. Newton’s First Law of Motion: Inertia

13. Balanced Force
Equal forces in opposite
directions produce no motion

14. Unbalanced Forces Unequal opposing forces produce an unbalanced force
causing motion

15. Force equals mass times acceleration.
Newton’s Second Law
Force equals mass times acceleration.
F = ma

16. WEIGHT is a measure of the force of ________ on the mass of an object
Newton’s Second Law
WEIGHT is a measure of the force of ________ on the mass of an object
measured in __________
gravity
Newtons

17. For every action there is an equal and opposite reaction.
Newton’s Third Law
For every action there is an equal and opposite reaction.

18. Newton’s 3rd Law
For every action there is an equal and opposite reaction.
Book to
earth
Table to
book

19. 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.

20. Action: tire pushes on road Reaction: road pushes on tire

21. Reaction: gases push on rocket
Action: rocket pushes on gases

22. (a) the force applied to the bat by the hands
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
(b) the force applied to the bat by the ball

23. What Laws are represented?

24. Review 1) Newton’s First Law:
Objects in motion tend to stay in motion and objects at rest tend to stay at rest unless acted upon by an unbalanced force.
2) Newton’s Second Law:
Force equals mass times acceleration (F = ma).
3) Newton’s Third Law:
For every action there is an equal and opposite reaction.

25. Study Jams: Newton’s Second Law Acceleration

26. Study Jams: Newton’s Third Law