Transcript S8P2 Energy Transformations - Mrs. Carnes

S8P2 Energy Transformations
• The Law of Conservation of Matter states that
matter can change in form as a result of
physical and chemical changes
• No matter is created or destroyed and the
overall mass of the matter does not change.
1
• The Law of Conservation of Energy states that
energy is neither created nor destroyed. It is
simply transformed from one type of energy
into another.
2
Kinetic and Potential Energy
• All energy can be classified into two
categories:
• A. kinetic
• B. Potential
3
Kinetic and Potential Energy
• Kinetic energy is energy
resulting from the motion of
an object
• The amount of kinetic energy
an object has is determined by the mass of
the object and the speed of the object.
4
Kinetic and Potential Energy
• Kinetic energy= ½ x mass x velocity2
• KE= ½ mv2
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Kinetic and Potential Energy
• Potential energy is stored
energy
• An object has potential energy
because of its position or
composition
6
Kinetic and Potential Energy
• Potential energy=
mass x height
PE= M x H
• Potential energy
stored in an object
can change into
kinetic energy
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Energy Transformations
• Energy can be
transformed or
changed from one
form to another
• Energy
transformations are
part of your daily life.
8
Energy Transformations
• Plants convert
electromagnetic energy
from sunlight into
chemical energy through
the process of
photosynthesis
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Energy Transformations
• When you eat vegetables,
your body converts some of
the stored chemical energy
into thermal energy to
maintain your body temperature and
mechanical energy to enable you to move
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Energy Transformations
• Chemical energy stored in
fuels, such as logs, is
converted to
electromagnetic energy and
thermal energy
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Energy Transformations
• Stars like the sun convert
nuclear energy into
electromagnetic energy
and thermal energy.
12
Energy Transformations
• The energy in vegetables you eat
is stored in the vegetables as
chemical energy
• The energy in fuels also is stored
chemical energy
* This energy is released when the fuels are
burned
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The Law of Conservation of Energy
• No matter how energy is transformed, energy
itself is not made or destroyed.
• Law of Conservation of Energy states while
energy may change from one
form to another, energy is neither
created nor destroyed
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The Law of Conservation of Energy
• In some energy conversions
energy may appear to be lost or
destroyed
• This occurs because energy
transfers are never completely
efficient
15
The Law of Conservation of Energy
• When energy is transferred
from one object to another or
when an object hits the
ground
• Some energy is usually
released as thermal energy
(heat)
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The Law of Conservation of Energy
• Friction is responsible for
this apparent energy loss.
• Friction is present any time
two objects are in contact
with one another
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The Law of Conservation of Energy
• When you roll a ball across a floor, the ball
comes to a stop because
of friction between the
ball and the floor
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The Law of Conservation of Energy
• A swing pendulum eventually stops because of
air resistance
• Air resistance is a form of friction that opposes
the motion of an object moving through air
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