#### Newton`s Laws of Motion

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Transcript Newton`s Laws of Motion

Newton’s Laws of Motion
Law #1 – Inertia
An object at rest will remain at rest
and an object in motion will remain
in motion at constant speed and in
a straight line unless acted on by
an unbalanced force.
This means that unless an
unbalanced force affects an object, it
will continue doing what it is doing –
either sitting still or moving!
Newton named this law The Law of
Inertia
“Inert” means not moving
So inertia is an object's tendency to stay
still!
Inertia Depends on Mass
The more mass an object has, the
harder it is to get it to move or to stop!
This is why seatbelts save people –
they prevent you from maintaining a
speed of 60-70 miles an hour when the
car suddenly stops!
Law #2 - F = m X a
The acceleration of an object
depends on the mass of the object
and the force applied.
Force
Mass
Force
Mass
It is harder to accelerate a more
massive object
Force
Mass
The more force is applied, the more acceleration will occur –
depending on mass!
Force
Mass
For example…
If you throw a bowling ball as
hard as you throw a baseball, it
will not accelerate as much - it
has more mass!
150 N
150 N
This equation works just like
the speed equation…
If an object accelerates at 10 m/sec with a mass of
50 kg, what is its force?
F= M x A
F = 50 x 10
F = 500 Newtons of force!
If a 1 kg basketball is thrown with a force of
80 N, what is its acceleration?
If a cow moves with an acceleration of 5
m/sec/sec and has a mass of 200 kg, how
much force is needed?
Law #3 – Action-Reaction
Force from hot gases
Whenever one
object exerts a
force on a second
object, the second
object exerts an
equal and opposite
force to the first.
Forward thrust
All forces act in pairs!
Whenever one force acts, a second must act.
THIS IS TRUE FOR EVERY FORCE IN THE
UNIVERSE!!!
When you jump off of the ground, you push down
and the ground pushes you back up.
If an astronaut floats away from his ship, he can
throw a wrench in the opposite direction, and be
propelled back toward the ship.