Transcript newtons laws_ppt

IPC
Newton’s 1st Law of Motion
• Newton’s 1st Law of Motion – Objects in
motion will stay in motion and objects at rest
will stay at rest…unless a force acts on them.
.
Newton’s 1st Law of Motion
• Newton’s 1st Law of Motion – Objects in
motion will stay in motion and objects at rest
will stay at rest…unless a force acts on them.
The ball will stay at
rest (not move) unless
the dog moves it.
Newton’s 2nd Law of Motion
• Newton’s Second Law of Motion - "F = ma:
the net force on an object is equal to the
mass of the object multiplied by its
acceleration.
Newton’s 2nd Law of Motion
• Newton’s Second Law of Motion - "F = ma:
the net force on an object is equal to the
mass of the object multiplied by its
acceleration.
•
• You bunt – the ball doesn’t go far. You swing
hard (more force), the object accelerates
faster.
Newtons Third Law of Motion
• Newton’s Third Law of Motion - To every
force or action, there is always an equal and
opposite reaction.
Newtons Third Law of Motion
• Newton’s Third Law of Motion - To every
force or action, there is always an equal and
opposite reaction.
The cannon has a backward kick when it is
fired.."
http://www.youtube.com/watch?v=b9qvt_L
S5sg
BALL
BUNT
CANNON
WHOLE BRAIN
Now turn to your partner and
NAME the 3 pics of Newton's LAWS
1.
2.
3.
Describe why the pics represent the LAWS..
..
Question
• What makes an object difficult to stop?
Momentum
Momentum
Momentum
Question
• A ball of mass 2 kg. is moving with a speed of
4 m/s. What is its momentum?
Answer
A ball of mass 2 kg. is moving with a speed of 4
m/s. What is its momentum
Momentum = (mass)(velocity)
= (2 kg)(4 m/s)
= 8 kg m/s
Mass
• More mass means more momentum (when
object is moving)
• Twice the mass means twice the momentum
(when object is moving at same rate of
speed).
Law of Conservation of Momentum
• For a collision occurring between object 1
and object 2 in an isolated system, the total
momentum of the two objects before the
collision is equal to the total momentum of
the two objects after the collision
• MV = MV
WHOLE BRAIN
Now turn to your partner and:
Name an object that has little mass but can have
a big momentum
Name an object that can move very slow but has
a very big momentum
What is the formula for momentum?
Centripetal Force
• Centripetal Force- force directed towards the
center of the circle for an object moving in a
circular motion.
Centripetal Acceleration
• Centripetal Acceleration – Acceleration
toward the center of a curved or circular
path.
Friction
• Friction - when 2 objects rub together. It
generates heat. Example (rub your hands
together)
SLIDING FRICTION
• Sliding Friction- is when
two objects are rubbing
against each other.
Putting a book flat on a
desk and moving it
around is an example of
sliding friction.
Rolling Friction
• Rolling friction- is the resistance that occurs
when a round object such as a train rolling on
a track or a ball rolling on a surface.
Static Friction
• Static friction - Static friction is a force
between two objects that are not moving
relative to each other.
WHOLE BRAIN
Turn to your partner and tell them about
• What happens when you
rub your hands
• sliding friction
• Rolling friction
• Static friction
• Centripetal Acceleration
Air Resistance
• Air resistance – Like
turbulence…….object
s slowing down in the
wind. Running into
the wind.
Weight
• Weight – Changes with gravity. It Is different
on every planet.
Mass
• Mass – Always remains the same. Triple
Beam balance / electronic scale can measure
mass.
Law of Gravitation
• Law of Gravitation - states that any two
objects exert a gravitational force of
attraction on each other. The moon’s
gravitational force causes tides.
Gravity Constant
• Gravitational Acceleration (gravity constant)
– 9.8 m/s2 (If you get thrown out of a plane,
you will accelerate 9.8 m/s2)
Projectiles
• Projectiles – Objects that are launched and
fly through the air (bullets, missiles)
WHOLE BRAIN
Turn to your partner and discuss
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Projectiles
The gravity Constant
The Law of Gravitation
Mass
Weight
Air Resistance