FORCE, ENERGY

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FORCE, ENERGY MOTIONSOL 4.2
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SPEED describes how fast an object is moving.
Speed can...
remain the same
increase
DECREASE
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ENERGY may exist in two states potential or
kinetic.
Potential energy is stored energy.
Kinetic energy is the energy of motion.
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Potential energy is stored energy.
What are some other examples of potential energy?
A baseball pitcher right before he throws the
ball.
A roller coaster at the top of a tall hill.
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Kinetic energy is energy of motion.
What are some other examples of kinetic energy?
A baseball pitcher as he throws the ball.
A roller coaster going down the hill.
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Kinetic energy is energy of motion.
ALL moving objects have kinetic energy.
When an object is in motion, it changes position
by moving in a direction
down
up
forward
backward
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A force is any push or pull that causes an
object to

• Forces transfer energy.
• When you throw a ball, the force of your arm
  pushes the ball into the air.
• Energy is transferred from your arm to the ball.
  

move
change direction
change speed
stop
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Without force, an object at rest will stay at
rest!
The pull of gravity is a force that might set an
object (or a skier) in motion. The pull or push
of a magnet is another force that can move
objects. The force you exert with your legs or
arms can set a ball in motion.
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Unless acted on by a force, an object in motion
will stay in motion!
An object will continue to move until a force
slows or stops it.

• The force stopping the object's motion might be
  an obvious one - the ground!

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The greater the force, the greater the change in
motion.
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The more massive an object, the less effect a
force will have on an object.
For example, it's easier to push a light plastic
ball than a more massive boulder. It's also
harder to stop a boulder when it is rolling down
a slope.
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FRICTION is the resistance to motion created by
two objects moving against each other.
.
the sled and the snow, for instance
FRICTION creates
HEAT!
Rub your hands together!
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The skier is standing at the top of the
mountain. Is the picture meant to show potential
or kinetic energy?
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Which object on the shelf has the greatest
potential energy?
  the red vase on the second shelf
  the blue vase on the top shelf
 
  the white box on the bottom shelf

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These passenger are just starting their descent.
What's happening?
potential energy is changing to kinetic energy