Transcript Newton`s Laws of Motion

Newton's Laws of Motion


An English
mathematician two
discovered three very
important laws for
physics
All ideas had to do
with motion
Newton's
st
1
Law of Motion
Describes motion produced by balanced forces

“An object at rest will remain at rest, and an
object that is moving at constant speed will
continue moving unless acted on by an
unbalanced force”
Newton's


st
1
Law
Also known as the “law of inertia”
Inertia= an object's resistance to changing its
state of motion

Object's don't want to change their motion
Newton's
nd
2
Law
Describes motion produced by unbalanced
forces.


“The net force on an object depends on its
mass and how fast it is accelerating”
F=ma (force=mass x acceleration)
Math Practice
A 52 kg water skier is being pulled by a
speedboat. The force causes her to
accelerate at 2 m/s. Calculate the force that
causes this acceleration.
More Math Practice
What mass will a pumpkin have if a force of 450
Newtons accelerates it to 110 m/s2 ?
One more problem…
A squirrel was gathering nuts in a pile. When he
came back to add to the pile, a seagull was
eating some of his peanuts. So he threw a .0015
kg peanut with a force of 15 Newtons at the
seagull. How fast did the peanut accelerate
through the air?
Newton’s 3rd Law of Motion
If you push an object into another object, what
happens???
Newton’s 3rd Law:
Forces always act in pairs. For every action force,
there is always an equal and opposite reaction
force.
Action force: the force that would occur first
Reaction force: the force that takes place
because of the action force
Newton’s 3rd Law
Newton’s 3rd Law is everywhere!!!
Give me some examples.
Birds flying, fish swimming, walking, sitting on a
chair
Which is the action force? Which is the reaction
force?
1. Hitting a nail with a hammer
2. A bug crashing into a windshield
3. Kicking a soccer ball
Newton’s 3rd Law
Always involves forces acting on two different
objects!!!