Newton’s 1 st Law

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# Newton’s 1 st Law - PowerPoint PPT Presentation

Newton’s 1 st Law. Law of Inertia. Question?. What is Newton’s first law of motion?. The Law of Inertia. The LAW OF INERTIA is Newton’s FIRST law of motion. Newton’s Law of Inertia. What does the Law of Inertia say?

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## Newton’s 1 st Law

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### Newton’s 1st Law

Law of Inertia

Question?
• What is Newton’s first law of motion?
The Law of Inertia
• The LAW OF INERTIA is Newton’s FIRST law of motion.
Newton’s Law of Inertia
• What does the Law of Inertia say?
• An object in M______ will remain in M______; An object at R______ will remain at R_____, until acted upon by a N___ F_____.

otion

otion

est

est

et

orce

What is inertia?
• Inertia- the tendency of an object to resist any change in its M______.

otion

Inertia
• The inertia of an object is related to its MASS. The GREATER the MASS the GREATER the I_____.
• Mass is the amount of MATTER an object has.

nertia

Question?
• Does a bowling ball have the same inertia as a tennis ball? Why?
The Law of Inertia at Work!

The penny is at rest and wants to remain at rest. When the string on the card is pulled with enough force, the penny will REMAIN AT REST.

The dishes are at rest and want to remain at rest. When the table cloth is pulled with enough force, the dishes will REMAIN AT REST.

PULL

The Law of Inertia at Work!

An object in motion wants to stay in motion. The person in the car is traveling at the same velocity as the car. When the car stops, the person wants to STAY IN MOTION. That is why you must wear your seatbelts!

The Law of Inertia at Work!

An object in motion wants to stay in motion. The test tube and the skateboard it is on is traveling at the same velocity. When the skateboard is stopped, the test tube wants to STAY IN MOTION.

### Newton’s Second Law

Force = Mass X Acceleration

F = m X a

Downward force of gravity

Boy pulling on rope and rock

Rock pushing down on table

Friction between rock and table and rope and hands

Table pushing up on rock

The relationship between mass and force….

ass

The more M______ an object has the more F______ required.

orce

Question….

If Marge applied the same amount of force to the grocery carts below, which will accelerate the slowest? Why?

The relationship between mass and acceleration….

ass

ccelerate

The more M________ an object has the less it will A ___________.

orce

ass

ccelerate

Newton’s Second Law says…….

If you apply a F_____________ to a M________ it will A___________.

FORCE

ACCELERATE

MASS

X

Newton’s 2nd Law says…

FORMULA: Force = Mass X Acceleration

F = m X a

F

m

a

F

m

a

X

CAN YOU DERIVE THE UNIT FOR FORCE ?

Force = Mass X Acceleration

= kg X m/s2

kg X m/s2

kg*m/s2 = NEWTON

FORCE is measured in NEWTONS !

F

m

a

X

Calculate the force needed to push a truck that has a mass of 2,000 kg with an acceleration of 0.05 m/s2.

100 N

100 N

2,000 kg

0.05 m/s2

F

m

a

X

Calculate the force needed to push a car that has a mass of 1,000 kg with an acceleration of 0.05 m/s2.

50 N

50 N

1,000 kg

0.05 m/s2

F

m

a

X

Calculate the acceleration of a 1,000 kg elephant if a force of 100 N is applied.

1,000 kg

0.1 m/s2

100 N

__?__ m/s2

100 N

1,000 kg

0.1 m/s2

### Newton’s Third Law

Action Reaction

string

air goes this way!

Let’s Observe….

string

Newton’s 3rd Law of Motion

ACTION - Air released

REACTION - Balloon moved

Let's observe some

different scenerios!

orce

Newton’s 3rd Law of Motion states:

When one object exerts a f____ on a second object, the second object exerts a f____ on the first that is e____ in size and o______ in direction.

orce

• qual

pposite

Newton’s 3rd Law…Sum it up…

ction

For every A_____ there is an equal and oppositeR______!

eaction

QUESTION???

Is it possible for you to touch without being touched? Think about it….

Remember…forces come in pairs.

Let's practice identifying

action-reaction forces

Billy-Bob shoots a hunting gun.Can you identify the action? Can you identify the reaction?

ACTION: Bullet exiting gun

REACTION: Gun pushing Billy-Bob back

Sarah is on ice skates and she pushes against a wall.Can you identify the action? Can you identify the reaction?

REACTION: Wall pushing back on Sarah

ACTION: Pushing on wall

Here is a water rocket.

Can you identify the action?

Can you identify the reaction?

REACTION: water rocket shooting upward

ACTION: Pressurized water exiting the rocket

Jimmy lifts his weights.

Can you identify the action?

Can you identify the reaction?

ACTION: Pushing up on weights

REACTION: Weights pushing down

Charlie hit a baseball.

Can you identify the action?

Can you identify the reaction?

REACTION: Ball hitting bat and the ball accelerating

ACTION: Bat hitting ball

Can you think of some

different action-reaction pairs?