Mechanical Work: More Practice

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Mechanical Work More Practice
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Mechanical Work More Practice
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Mechanical Work More Practice
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Mechanical Work More Practice
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Mechanical Work More Practice
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Mechanical Work More Practice
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Mechanical Work More Practice
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Mechanical Work More Practice
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Mechanical Work More Practice
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Gravitational Potential Energy

• SPH4C

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Gravitational Potential EnergyLearning Goal

• The student will be able to explain the concept
  of gravitational potential energy and conduct an
  inquiry to explore the work and power output when
  an object is lifted.

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Working Against Gravity

• If you lift an object a distance Dh at a constant
  velocity, the vertical forces must be

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Working Against Gravity

• If you lift an object a distance Dh at a constant
  velocity, the vertical forces must be balanced
  and the applied force that does the work must be
  equal in magnitude but opposite in direction to
  the

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Working Against Gravity

• If you lift an object a distance Dh at a constant
  velocity, the vertical forces must be balanced
  and the applied force that does the work must be
  equal in magnitude but opposite in direction to
  the force of gravity.

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Gravitational Potential Energy

• The energy that this work is increasing is the
  objects gravitational potential energy.

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Gravitational Potential Energy

• Although gravitational potential energy is often
  written as
• where h is understood as being relative to some
  reference point.

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Gravitational Potential Energy

• Note that there is no designated spot on Earth
  that is your reference point with zero height.
  You must designate the reference point.

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Example 1

• An object of mass 3.0 kg is lifted at constant
  velocity from a height of 1.0 m to a height of
  2.5 m. Find the increase in gravitational
  potential energy of the object.

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Example 1

• An object of mass 3.0 kg is lifted at constant
  velocity from a height of 1.0 m to a height of
  2.5 m. Find the increase in gravitational
  potential energy of the object.

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Example 1

• An object of mass 3.0 kg is lifted at constant
  velocity from a height of 1.0 m to a height of
  2.5 m. Find the increase in gravitational
  potential energy of the object.

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Power

• Power is the rate at which work is performed or
  energy is transferred
• It has units of J/s or Watts (W).

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Example 2

• An object of mass 3.0 kg is lifted at constant
  velocity from a height of 1.0 m to a height of
  2.5 m in 2.0 s. Find the power output.

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Example 2

• An object of mass 3.0 kg is lifted at constant
  velocity from a height of 1.0 m to a height of
  2.5 m in 2.0 s. Find the power output.

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Example 2

• An object of mass 3.0 kg is lifted at constant
  velocity from a height of 1.0 m to a height of
  2.5 m in 2.0 s. Find the power output.

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Example 3

• An object of mass 3.0 kg is lifted at a constant
  velocity of 0.75 m/s up. Find the power output.

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Example 3

• An object of mass 3.0 kg is lifted at a constant
  velocity of 0.75 m/s up. Find the power output.

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Example 3

• An object of mass 3.0 kg is lifted at a constant
  velocity of 0.75 m/s up. Find the power output.

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More Practice

• Upstairs Inquiry Activity
• More Practice Gravitational Potential Energy