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Energy Transformation

Phy. Sci.

Law of Conservation of Matter• 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.

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Kinetic and Potential Energy• All energy can be classified into two categories:• A. kinetic• B. Potential

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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.

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Kinetic and Potential Energy• Kinetic energy= ½ x mass x velocity (2)• KE= ½ mv(2)

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Kinetic and Potential Energy• Potential energy is stored energy• An object has potential energy because of its position or composition

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Kinetic and Potential Energy• Potential energy= mass x heightPE= 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.

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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, you 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.

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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

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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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