Energy

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Energy
ALL ENERGY has the ABILITY to do WORK!! Like
WORK , ENERGY will be MEASURED in JOULES (J)
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How is all energy divided?
All Energy
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What is Potential Energy?

• Energy that is stored and waiting to be used later

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Potential Energy

• The energy that an object has because of the
  position, shape, or condition of the object is
  called potential energy.
• Potential energy is stored in many ways.
• Elastic potential energy is the energy stored in
  any type of stretched or compressed elastic
  material, such as a spring or a rubber band.
• Gravitational potential energy is the energy
  stored in the gravitational field which exists
  between any two or more objects.
• Chemical potential energy is energy stored in a
  compound or element that can be released during a
  chemical change.

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What is Gravitational Potential Energy?

• Potential energy due to an objects position
• P.E. mass x
• height x gravity

Dont look down, Rover! Good boy!
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Potential Energy

• Gravitational potential energy depends on both
  mass and height.
• Gravitational Potential Energy Equation
• grav. PE mass ? free-fall acceleration ?
  height
• Epg mgh ? units kg m/s2 x m
  or Joules
• The height can be relative.
• The height used in the above equation is usually
  measured from the ground.
• However, it can be a relative height between two
  points, such as between two branches in a tree.

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What is Elastic Potential Energy?

• Potential energy due compression or expansion of
  an elastic object.

Notice the ball compressing and expanding
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Potential Energy

• Elastic potential energy depends on the distance
  an object can be compressed or stretched.
• Elastic Potential Energy Equation
• elas. PE ½ x spring constant ? (stretch
  distance)2
• Es ½ kd2 ? units N/m x m2 or Joules (J)
• The spring constant (k)
• Is determined by measuring the force needed to
  stretch or compress a spring.
• k Force/distance ? units N/m

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What is Chemical Potential Energy?

• Potential energy stored within the chemical bonds
  of an object

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What is Kinetic Energy?

• Energy an object has due to its motion
• K.E. .5(mass x speed2)

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Kinetic Energy

• The energy of a moving object due to the objects
  motion is called kinetic energy.
• Kinetic energy depends on mass and speed.
• Kinetic Energy Equation

? units kg m2/s2 or J

• Kinetic energy depends on speed more than mass.

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Using you book

• Complete practice problems 1-4 1-3
• From pages 393 395