Energy

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Energy

• PESS 1

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What is Energy?

• The ability to do work or cause change is energy
• When work is done on an object by another object
  energy is transferred between the objects
• Two basic types of energy
• Kinetic and potential energy

3
What is Energy?

• Kinetic energy
• energy of motion
• Depends on mass and velocity of the moving object
• Calculating kinetic energy
• K.E. ½ mass x velocity2
• Units are J (joules)

4
What is Energy?

• Potential energy
• Energy of position or stored energy
• Energy related to an objects height is called
  gravitational potential energy
• Calculating gravitational potential energy
• G.P.E weight x height
• Units are also J (joules)
• Elastic potential energy
• When an object is stretched or compressed

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Forms of Energy

• Mechanical energy
• Energy associated with position and motion of an
  object (basically, a combination of potential and
  kinetic energy)
• Calculated by
• Mechanical energy P.E K.E.

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Forms of Energy

• Thermal energy
• The kinetic and potential energy of the particles
  that make up an object
• The faster the particles are moving the more
  thermal energy
• Thermal energy is also known as heat

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Forms of Energy

• Electrical energy
• A moving stream of energy also known as,
  electricity
• Chemical energy
• Potential energy stored in chemical bonds
• Nuclear energy
• Energy stored in the nucleus of an atom

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Section 2 Forms of Energy

• Electromagnetic energy
• Energy that travels in waves
• Can be either electrical or magnetic

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Section 3 Energy Transformations and conservation

• Energy transformations
• Most forms of energy can be transformed into
  other forms
• Single transformations examples
• Electrical energy in cell phones transfers to
  electromagnetic energy to send the signal to
  other cell phones
• Chemical energy in food transfers into mechanical
  energy used by muscles

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Energy Transformations and Conservation

• Energy transformations
• Multiple transformations
• Car engines start with chemical energy in fuel,
  transferred into thermal energy when the fuel
  burns, then transferred into mechanical energy to
  move the car

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Energy Transformations and Conservation

• Conservation of energy
• Law of conservation of energy states that energy
  cannot be created or destroyed
• This means that the total energy remains the same
  it only changes forms