On each Page, you are to describe that law of motion, in your own words, and provide an illustration that demonstrates that law of motion.

• Neatness will be taken into consideration for your grade.– Requirements for each page:

1. Front Page is the title Page- Newton’s Laws & Your Name

2. Newton’s First Law of Motion3. Second Law of Motion4. Third Law of Motion 5. Universal Law of Gravitation6. Last Page is One Picture with all Laws

applied to it.

Bill Nye Forces

Laws of Motion

New

ton’s

Forces

• A force is any push, or pull, on an object– Measured in Newtons - N– Vector Quantity – Direction Matters

• Same = add Opposite = Subtract

Free Body DiagramsFree Body Diagrams(Force Diagrams)(Force Diagrams)

– Represent all forces acting on an object

• Many types of forces!

– Draw all forces acting on an object & Label

– To scale– Proper direction

Net Force

same as

Sum of all forces acting on an object is called net force or total force

BRICK

3 Newtons5 Newtons

8 Newtons

Check Yourself

?

Weight

• Weight is a force– Force due to gravity (more on that later!)

• Acts downwards (towards earth) always!!!

• W=mg

g=9.8m/s/s

Normal Force

Solid surfaces exert a force, called a normal force (support force), on objects pressed against them.

100 NewtonSupport force

Downward force (weight) balanced by upward force (normal).

100 NewtonGold Brick

Weight Practice

• Calculate the Weight of:• 10 kg book x 9.8 m/s/s = 98 Newtons

• 500 kg table x 9.8 m/s/s = 4900 Newtons

• 100 kg person x 9.8 m/s/s = 980 Newtons

Friction

• Always opposes the motion of the object

Force Diagram Practice

• Draw out the following force diagrams in Your Notebook– A text book on the table– A ball falling– Holding an apple in your hand– Pushing a shopping cart to the right

Force Diagram Practice

Newton’s First Law of Motion

Law of InertiaLaw of Inertia

An object at rest remains at rest and an object in motion* remains in motion, unless acted upon by an outside force

*Moving in a straight line with

constant speed.

More mass = More Inertia =

More Resistance to Change its State of Motion

Think of Football PlayersThink of Football Players

Or Pushing a shopping cartOr Pushing a shopping cart

So……..

• If this law is true….why does the object stop???

Is Newton Wrong?!?!

Newton’s Law is True!

Another force acts on the object, which slows the object down

This force is called Friction

Friction

• Always opposes the motion of the object

On the surface….

Origin of friction is molecular interaction between solid surfaces.

• Friction is complicated. • Friction depends on support force and

on properties of the surface.