Nature and Nature's laws lay hid in night,

1

• Nature and Nature's laws lay hid in night, 
• God said 'Let Newton be!', and all was
  light.    - Alexander Pope

2
Newtons Laws

• understanding force and motion

3
Last time

• Inertia, Mass
• Mass vs. Weight
• Net Force
• Force as a Vector Quantity Book on table
  Support Force
• Pull the book Frictional Force
• Speed and Velocity
• Acceleration

4
Free Fall

• Free falling objects are accelerated by the
  earths pull.
• All fall with the same acceleration (Galileo)
• Free Fall Acceleration 10 m/s²
• Also called the acceleration of gravity, g

5

• Nature and Nature's laws lay hid in night, 
• God said 'Let Newton be!', and all was
  light.    - Alexander Pope

6
Sir Isaac Newton

• 1643-1727
• English Mathematician and Physicist
• Revolutionized both subjects
• Math Calculus
• Physics Optics
• Force and Motion (Three Laws)
• Law of Universal Gravitation

7
The First Law

• Basically a restatement of Galileos Idea
• An object in motion or at rest remains in that
  state unless acted upon by a net external force
• Inertia Property of object to resist changes in
  motion

8
The Second Law

• The net force on an object equals the mass of the
  object times its acceleration.
• Or in a slightly altered form
• Acceleration F/m

9
Second Law and Free Fall

• This shows why two objects with different masses
  fall (and accelerate to the earth) at the same
  rate.
• Galileo knew the fact, but not the why
• F/m constant g
• Air Resistance throws this off (ball of paper)

10
Terminal Velocity
11
Push on the wall

• What happens when I push on the wall?
• Am I exerting a force on the wall?
• or is it exerting a force on me?

12
The Third Law

• Whenever an object exerts a force on a second
  object, the second object exerts an equal and
  opposite force on the first.
• Action lt-gt Reaction Force

13
Homework

• Ch. 2
• Exer. 1,8,13,16,25,27,33,42
• Prob. 1,2,6,13