IPC Chapters 4 and 5

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IPC Chapters 4 and 5

• Work and Energy

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Work, power, and machines

• ___________ is defined as the amount of force
  applied to an object over a specific distance.
• Therefore, if an object is not moved any
  distance, then there is no work done on the
  object.
• Work ___________ ___________
• Wfd

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Work, power, and machines

• Remember that ___________
• Therefore, the units of force are

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Work, power, and machines

• That is the same as a ___________
• Therefore, the unit of work is a Newton Meter,
  or a Joule (J)

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Units of Work
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Work, power, and machines

• ___________ is defined as the amount of time it
  takes to do a defined amount of work.
• ___________ ___________ ___________

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Work, power, and machines

• Power is measured in ___________.
• 1 ___________ is 1J / s
• Practice Problems pages 285 1-5 and 287 1-5

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Mechanical Advantage

• ___________ multiply and re-direct forces.
• Machines can help us in several different ways
• Multiply an ___________ force
• Redirect an ___________ force
• Increase an ___________ distance
• The mechanical ___________ of a machine tells how
  much that machine helps with a certain job.

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Mechanical Advantage

• A ___________ with a mechanical advantage of one
  is not multiplying a force, but may be helping in
  other ways.
• A ___________ with a mechanical advantage of more
  than one is multiplying the input force so that
  the output force is greater than the input force.

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Mechanical Advantage
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Mechanical Advantage

• 1-5 practice problemspage 290

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Simple Machines

• The most basic machines are called ___________
  machines
• There are six simple machines
• ___________
• ___________
• ___________ ___________
• ___________
• ___________
• ___________ ___________

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Simple Machines

• Levers
• All ___________ have a rigid arm that rotates
  around a point called a fulcrum
• There are three ___________ of levers, based upon
  the location of the fulcrum, and the input and
  output forces.

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Simple Machines

• 1st class leverbasic teeter-totter. This is a
  lever with the ___________ in the middle, with an
  input force on one end, and an output force in
  the opposite direction on the other.
• Examplesclaw hammer, teeter-totter, plyers (two
  sets together).

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Simple Machines

• 2nd class leverlever with the fulcrum at one
  end, and the input force at the other end.
• The output force is in the middle.
• Examplewheel barrow, ___________
• 3rd class leverlever with the fulcrum at one
  end, the input force in the middle, and the
  output force at the other end.
• Example-- ___________

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Simple Machines

• ___________modified lever.
• Pulleys redirect forces, and can increase
  mechanical advantage, if used correctly and in
  combination.
• ___________ ___________ pulley connected to a
  shaftexamplescrewdriver, steering wheel, so
  onincreases input distance.

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Simple Machines

• ___________ planeincreases input distance, to
  increase mechanical advantage.
• Example--Ramp
• ___________2 inclined planes back to back
• Exampleaxe
• ___________inclined plane wrapped around a
  cylinder.

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Compound Machines

• ___________ machinesmachines made up of two or
  more simple machines put together.
• AssignmentCreate a compound machine using two or
  more simple (or compound) machines that you have
  laying around your houseMajor Grade.

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Compound Machine

• You will be graded on the following questions
• Is it a compound machine50 points
• How did you construct it20 points
• What is it useful for30 points
• Due Monday, or its a late grade on Tuesday.
  After Tuesday, it is a zero.

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Energy

• Energy is the ability to do work, and is measured
  in Joules (J)
• There are 2 types of energy
• ___________ ___________
• ___________ ___________
• Potential energy is energy that is storedready
  to do work at any moment.

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Energy

• There are 2 types of potential energy
• Elastic potential energy
• Gravitational potential energy
• Elastic ___________ energy is energy stored in
  something that is stretchedsuch as a rubber
  band, or spring.
• ___________ potential energy occurs when an
  object is off the ground, and has the potential
  to fall.

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Energy

• ___________ potential energy depends upon both
  mass and height.

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Energy

• ___________ energy is energy in motion.
• ___________ energy is the energy displayed when
  an object is doing work (moving).
• The ___________ an object is moving (I.e. the
  more kinetic energy it has), the more work it is
  doing, and vice versa.
• The equation for kinetic energy is

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Energy
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Energy

• Practice problems
• 1-4 Page 299
• 1-3 Page 301

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Energy

• The sum of all energy in a system (potential plus
  kinetic) is called mechanical energy.
• In ___________ systems, energy is constantly
  converted from potential to kinetic, and back
  again.

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Conservation of energy

• The law of ___________ of energy states that
  energy may not be created nor destroyed, only
  changed from one form to another.
• With each ___________(kinetic to potential, or
  back), there is a loss of some of the mechanical
  energy (energy of the system).

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Conservation of energy

• This is usually due to forces such as
  ___________.
• ___________ is most often lost from a system as
  heat and sound.
• This is what happens to most ___________.
• Therefore, you cannot get all of the work out of
  a machine that you should.

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Conservation of energy

• The ___________ of useful work out of a machine,
  compared to work input is called the machines
  efficiency.
• This is expressed as.

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Conservation of energy