1. Newton’s Laws of Motion
Chapter 4 Sections 1, 2, and 3
Glencoe: Pages

2. Newton’s 1st Law
An object at rest will remain at rest, and an object in motion will remain in motion unless acted on by an outside force
Inertia – the tendency of an object to continue its current state of motion, at rest or motion
Example: pulling a tablecloth out
from under the table setting, or a car running into a wall

3. Newton’s 1st Law
If the car were to abruptly stop and the seat belts were not being worn, then the passengers in motion would continue in motion. The passengers would likely be propelled from the car and be hurled into the air becomes projectiles and continue in projectile-like motion.

4. Newton’s 1st Law
In this example, the ladder continues in motion because no outside force changes its original motion, until the ladder hits the ground.

5. Newton’s 2nd Law
The unbalanced force acting on an object equals the object’s mass times the object’s acceleration
 F = m•a
SI units for force = Newton
***(1 N = 1 kg·m/s2)***

6. Newton’s 2nd Law
It is obviously takes less force to make the ball accelerate because the ball has less mass.

7. Newton’s 2nd Law
Example: Think of the force required to push an empty shopping cart, and the force required to push a full shopping cart. What is the difference?
More force applied = greater acceleration

8. Newton’s 2nd Law Weight ≠ Mass
Weight – the measure of gravity pulling on an object
Mass – the measure of the amount of matter
in an object

9. Newton’s 2nd Law Weight influences shape
On land a supporting skeleton is required
 In water less body support required because the water helps lift the mass
*Animals can be larger if they live in the water

10. Newton’s 2nd Law
Free fall – motion of a body when the only force acting on it is gravity
Terminal velocity – maximum velocity reached when air resistance pushes up as much as gravity pulls down
 Force of gravity pulling down = force of air resistance pushing up

11. Newton’s 3rd Law
For every action there is an equal but opposite reaction
***Action and reaction forces are applied to different objects
 These forces occur in pairs at the same time, but do not cancel out!
Example: rocketry

12. Newton’s 3rd Law
Actions and Reactions