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Newton’s 1 st Law. November 27. Mrs. Brown. Newton’s First Law : Objects at Rest stay at rest, objects in motion, stay in motion until acted on by an unbalanced force. Warm - Up: Write Newton’s First Law in your journal. Today’s Agenda: Complete Warm-Up Review Explore Newton’s Laws

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Newton’s 1st Law

November 27

Mrs. Brown

Newton’s First Law:

Objects at Rest stay at rest, objects in motion, stay in motion until acted on by an unbalanced force.

• Warm - Up:
• Write Newton’s First Law in your journal.
• Today’s Agenda:
• Complete Warm-Up
• Review
• Explore Newton’s Laws
• In-Depth – Newton’s 1st Law

200 N

85 N

What is the Net Force?

Balanced Force

Equal forces in opposite

directions produce no motion

Explain why the forces are balanced.

Unbalanced Forces

Unequal opposing forces

produce an unbalanced force

causing motion

What is the magnitude of forces on the truck?

Background

Sir Isaac Newton

(1643-1727)

He was an English scientist and mathematician famous for his contributions to our understanding of motion and gravity.

Newton’s First LawINERTIA

An object at rest tends to stay at rest and an object in motion tends to stay in motion unless acted upon by an unbalanced force.

Newton’s First Law (Law of Inertia)
• INERTIA is the tendancy of an object to ______________ in the motion of the object
• more _____ means more ______

resist CHANGE

mass

Inertia

INERTIA

more MASS means more INERTIA

Objects at rest, tend to stay at rest…

… until acted on by an unbalanced force!

Newton’s First Law is also called the Law of Inertia

Inertia:

the tendency of an object to resist changes in its state of motion

Inertia

Objects in motion, tend to stay in motion…

… until acted on by an unbalanced force.

If objects in motion tend to stay in motion, why don’t moving objects keep moving forever?

Things don’t keep moving forever because there’s almost always an unbalanced force acting upon them.

A book sliding across a table slows down and stops because of the force of friction.

If you throw a ball upwards it will eventually slow down and fall because of the force of gravity.

In outer space, away from gravity and any sources of friction, a rocket ship launched with a certain speed and direction would keep going in that same direction and at that same speed forever.

• There are four main types of friction:

Friction!

• Sliding friction: ice skating
• Rolling friction: bowling
• Fluid friction (air or liquid): air or water resistance
• Static friction: initial friction when moving an object
Examples of Inertia
• Headrests are placed in cars to prevent whiplash injuries during rear-end collisions.
• While riding a skateboard (or wagon or bicycle), you fly forward off the board when hitting a curb, a rock or another object which abruptly halts the motion of the skateboard.

Inertia… it will get you every time.

Watch where you’re going.

More Examples from Real Life

A powerful locomotive begins to pull a long line of boxcars that were sitting at rest. Since the boxcars are so massive, they have a great deal of inertia and it takes a large force to change their motion. Once they are moving, it takes a large force to stop them.

On your way to school, a bug flies into your windshield. Since the bug is so small, it has very little inertia and exerts a very small force on your car (so small that you don’t even feel it).

Newton’s First Law

Activity 1: Egg Drop

Activity 2: Crazy Coin Trick

Activity 3: Coin-In-A-Cup

Activity 4: “Bombing the Basket”

Activity 5: Tablecloth Trick

Activity 6: Broken Nose or Whiplash?

Exit Slip:

In your own words write the First Law of Motion.

Draw a picture that demonstrates the 1st Law of Motion.

Newton’s 1st Law

November 28

Mrs. Brown

Reminders:

FINISH DISCUSSION QUESTIONS on the BACK of LAB SHEET for HOMEWORK!!!

• Warm - Up:
• How does Newton’s First Law apply to the picture to the right?
• Today’s Agenda:
• Complete Warm-Up
• Review Net Force
• Explore Newton’s Laws of Inertia Lab
• 5. Homework – finish last page of Lab

Warm Up:

How is Newton’s 1st Law demonstrated in the picture below?

The graph probably depicts --

• A jogger running at a constant speed in the park
• A child skipping for 15 meters then walking for 20 meters
• A car driving at a constant speed, stopping at a red light, then continuing at a constant speed
• D. A student sitting in a desk

What is the average speed of the object in the graph?

What was Michael’s average speed?

Which graph best shows Michael’s motion?

Speed

Distance

Distance

Time

Time

Time

What is the Net Force on the Object?

20 N

10 N

If the object is moved for 100 cm, how much work was done?

Newton’s First LawINERTIA

An object at rest tends to stay at rest and an object in motion tends to stay in motion unless acted upon by an unbalanced force.

Newton’s First Law (Law of Inertia)
• INERTIA is the tendancy of an object to ______________ in the motion of the object
• more _____ means more ______

resist CHANGE

mass

Inertia

INERTIA

more MASS means more INERTIA

Objects at rest, tend to stay at rest…

… until acted on by an unbalanced force!

Inertia

Objects in motion, tend to stay in motion…

… until acted on by an unbalanced force.

• There are four main types of friction:

Friction!

• Sliding friction: ice skating
• Rolling friction: bowling
• Fluid friction (air or liquid): air or water resistance
• Static friction: initial friction when moving an object

Newton’s First Law

Activity 1: Egg Drop

Activity 2: Crazy Coin Trick

Activity 3: Coin-In-A-Cup

Activity 4: “Bombing the Basket”

Activity 5: Tablecloth Trick

Activity 6: Broken Nose or Whiplash?

Newton’s 2nd Law

November 29

Mrs. Brown

Reminders:

Projects Due December 17!!

• Warm - Up:
• In your journal write - “Newton’s Law of Inertia would apply at a grocery store when….”
• Today’s Agenda:
• Turn in Homework
• Demonstration of Newton’s 2nd Law of Motion

Some fun demonstrations of the Law of Inertia.

Newton’s Law of Force

Acceleration: any change in velocity….

___________, ____________ or ___________

Slows down

turns

Speeds up

Newton’s Law of Force

F = ma

To find MASS, you would ___________ force by acceleration.

To find ACCELERATION, you would _____________ force by mass.

F

DIVIDE

a

m

DIVIDE

What does F = ma say?

that the mass or the speed of an object determines the amount of force required to move it.

Something very massive that’s moving very slowly, like a glacier, can still have great force.

Something very small that’s moving very quickly, like a bullet, can still have a great force.

Mass affect Acceleration

Force affects acceleration

Mass

Force

If an equal amount of force is applied to the two cars above, the heavier car will accelerate _____________.

MORE SLOWLY

A bowling ball and a soccer ball are both pushed with 1kN of force, why does the soccer ball accelerate more?

Newton’s Second Law

Acceleration: any change in velocity.

If the dog increases the force, the acceleration will __.

If the mass of the rock increases, the acceleration will __.

EXIT SLIP:

Give me an example of

Newton’s 2nd Law at a(n)…

Water Park.

Department Store.

Sporting Event.

2. What would happen to the acceleration if one person pushed two people on the swing? Why?

Newton’s 3rd Law

December 2nd

Hardy

Reminders:

Projects Due January 10th!

• Warm - Up:
• Answer # 4 – 5 on your HOMEWORK.
• Today’s Agenda:
• Discussing Newton’s 3rd Law of Motion.
• Rocket Launch Lab.
• HOMEWORK

Lets REVIEW…

Who can tell me what Newton’s 1st Law, the Law of Inertia says?

Who can tell me what Newton’s 2nd Law, the Law of Force says?

Why do linemen look like this

And receivers look like this

Force = mass x acceleration

F = m x a

What will be the acceleration of the weight when the force is applied downward on the pulley?

300N

100 kg

If the two skaters apply a force of 50 Newtons in opposite directions, which skater will have a greater acceleration?

Hardy

Mrs. Pfoh

100 kg

80 kg

WHY???

Newton’s Law of Action & Reaction

For every action there is an equal and opposite reaction.

ACTION

REACTION

Balloon

Rocket

Demonstration

What energy transformations did you observe in the balloon rocket?

How we could calculate the speed of the balloon rocket?

How would adding a coin to the top of the balloon change the acceleration of the rocket?

How would blowing more air into the balloon change the acceleration of the rocket?

How does Newton’s 1st Law apply to the balloon rocket?

When the balloon is blown up, the air pressure pushes outwardly on the balloon.

When the balloon is released, the force of the air leaving the opening = the ACTION force.

The REACTION or result is the balloon flying in the OPPOSITE direction.

Did the ball exert a force on the man’s face? (action)

Can you tell the man’s face exerted a force back on the ball? (reaction)

If Luke applies a force to the 25 kg box, and it accelerates at a rate of 4 m/s, what is the force Luke applied to the box?

4 m/s

25 kg

Think about it . . .

Why does it hurt so much when you stub your toe?

10 N of force right back

10 N of force

Ouch!!!

Newton’s 3rd Law

November 30

Mrs. Brown

Reminders:

Projects Due December 17!

• Warm - Up:
• Complete the Warm-Up (1/2 sheet of paper)
• Today’s Agenda:
• Balloon Rocket Demo
• Discussing Newton’s 3rd Law of Motion.
• Rocket Launch Lab.
• HOMEWORK
• EXIT SLIP:
• Watch Mrs. Brown goooooooooooo& Write 2 sentences describing the law of motion.
Review

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.

Newton’s Second Law:

Force equals mass times acceleration

(F = ma).

Newton’s Third Law:

For every action there is an equal and opposite reaction.

Vocabulary

Inertia:

the tendency of an object to resist changes in its state of motion

Acceleration:

a measurement of how quickly an object is changing speed

What does this mean?

Gravity is pulling you down in your seat, but Newton’s Third Law says your seat is pushing up against you with equal force.

This is why you are not moving.

There is a balanced force acting on you– gravity pulling down, your seat pushing up.

1. Tape the paper body around the film canister. Make sure that the lid of the film canister is on the bottom end of the tube. Tape the construction paper in place.

2. Take off the cover of the film canister. Add 5 mL of water and ½ an Alka-Seltzer tablet and cover quickly.

3. Set the rocket down so that the nose cone points up.

4. Stand back and get ready for blast-off!!

3-2-1 Blastoff!!

You have 6 minutes