1.What does Net Force mean? 2.What is Newton’s 1 st Law? The Questions.

1. What does Net Force mean?

2. What is Newton’s 1st Law?

The Questions

Force changes motion

A force is a push or pull

BUT

IT IS THE “NET FORCE” THAT WE CARE ABOUT!!

Net ForceNet Force is the sum of

the forces acting on an object in EACH direction (x or y).

What is the Net Force acting on the golf ball??

x-Direction:

(+20N) + (-10N) = +10N

y-Direction:

(+5N) + (-5N) = 0N

-10N+20N

-5N +5N

Gravity

(+300N) + (+300N) = +600N

(+Normal Up) + (-Gravity down) = 0N

Is this object in Equilibrium?

Newton’s 1st Law: The Law of Inertia

Official Version:

“An object at rest will stay at rest and an object in motion will continue in motion at a CONSTANT VELOCITY unless acted on by a NON-0 Net force.”

Newton’s 1st Law: The Law of Inertia

Newton’s 1st Law in simple English: Objects that are not moving will not

move unless pushed by a non-0 NET force. Objects that are moving will keep moving at the same velocity unless a non-0 NET force pushes on them.

If the Net Force on an object is 0N, an object at rest (velocity=0m/s) will stay at rest (velocity=0m/s).

If an object is acted upon by an unbalanced force (Net Force0), its motion (VELOCITY) will change.

Inertia is a property of matter!

Who said this?? Billy Nye

Inertia is the property of an object that resists changes in motion (VELOCITY).

Inertia = mass

Inertia is the same thing as an objects mass.

Inertia is measured with kilograms.

Which ball has more inertia?

Newton’s 1st Law: The Law of Inertia

Bowling Ball

1. What does Net Force mean?

a) The sum of all of the forces acting on an object.

2. What is Newton’s 1st Law?

a) Known as the “Law of Inertia”

b) An object’s velocity will change if the net force is not 0.

The Answers

Newton’s First Law is known as:

Law of A

ction ...

Law of C

onserv.

..

Law of In

ertia

Law of C

onserv.

..

Law of t

he Ben...

0% 0% 0%0%0%

1. Law of Action and Reaction

2. Law of Conserved Mass

3. Law of Inertia4. Law of Conserved

Energy5. Law of the

Benevolent Dictator

Inertia is measured in units of

Meters

Lite

rs

Kilogra

ms

Seco

nds N

/kg

m/s2

0% 0% 0%0%0%0%

1. Meters2. Liters3. Kilograms4. Seconds5. N/kg6. m/s2

What has more Inertia?

Baseball

Skyb

all

Bowling B

all

Beach Ball

Golf B

all

Ping Pong B

all

0% 0% 0%0%0%0%

1. Baseball2. Skyball3. Bowling Ball4. Beach Ball5. Golf Ball6. Ping Pong Ball

A Net Force of +100N acts on an object. That object will

Stay i

n motion...

Stay a

t rest.

Have

its veloc..

.

0% 0%0%

1. Stay in motion.2. Stay at rest.3. Have its velocity

changed.