1. Change an object’s motion Do not change an object’s motion
Net force = 0 N
Push or pull
Have direction
Net force does not equal 0 N B O T H
Balanced
Forces
Unbalanced
Forces

2. Unbalanced
Forces B O T H
Balanced
Forces
Doesn’t change an object’s motion
Change an object’s
motion
Push or pull
Have direction
Net force = 0 N
Net force does not
equal 0 N

3. Newton’s Laws of Motion
9.3
Pgs

4. Take a look
at this!!

5. Newton’s First Law of Motion
An object at rest will stay at rest unless acted upon by a nonzero net force.
An object moving will continue moving unless acted upon by a nonzero net force.

6. Because of inertia, I resist
changes in motion. When
the coaster accelerates over
a hill, inertia keeps me
moving at a constant
velocity. I feel tossed around.
objects only change motion when a nonzero net force acts on them.

7. Newton’s First Law video clip

8. Inertia
Resistance to change in motion.

9. Inertia depends on mass
The greater the mass of an object, the greater its inertia, and the greater the force required to change its motion.

10. Newton’s Second Law of Motion
An object’s acceleration depends on its mass and on the net force acting on it.
Acceleration = Net force
Mass
Net force = Mass X Acceleration

11. More dogs could
be added OR
passengers could
be removed.
Dogs could be
removed OR
passengers could
be added.

12. 100 N/50 kg = 2 m/s2
50 kg X 9.8 m/s2 = 490 N

14. Force = Mass X Acceleration
It would be cut in half to
Become 1 m/s2
2 kg X 2 m/s2 = 4 N
among force, mass, and acceleration.

15. Newton’s Third Law of Motion
If one object exerts a force on another object, then the second object exerts a force of equal strength in the opposite direction on the first object. For every action there is an equal but opposite reaction.

16. Action-Reaction Pairs examples…

17. Action-Reaction Pairs

18. Newton’s Third Law of Motion

19. for every action force there is
an equal and opposite reaction
force.