The work that you do on a machine is called ________

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Wednesday, January 11 Warm-up (everyone should
be writing this down.)
The work that you do on a machine is called
________ The work done by the machine on an
object is called _________
work input.
work output.
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S8P3.c. Demonstrate the effect of simple machines
on work. (lever, inclined plane, pulley, wedge,
screw, and wheel and axle)
MYP QUESTION How do machines make work
easier? AoI Human
Ingenuity IB Learners Thinker,
Open-Minded Work Session Notes Simple
Machines
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Opening
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Machines Increase Power It may take you longer
to sand a wooden shelf by hand than by using an
electric sander, but the amount of energy needed
is the same either way. Only the power output is
lower when you sand the shelf by hand.
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Chapter 8
Power How Fast Work Is Done

• Calculating Power Power is the rate at which
  energy is transferred. To calculate power (P),
  you divide the amount of work done (W) by the
  time (t) it takes to do that work

• The unit used to express power is joules per
  second (J/s), also called the watt. One watt (W)
  is equal to 1 J/s.

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P W P 150J P 15 J/s
t 10 s
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• Same Work, Different
• Force Machines make work easier by changing the
  size or direction of the input force.
• The Force-Distance Trade off
• When a machine changes the size of the force, the
  distance through which the force is exerted must
  also change.

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Chapter 8
Mechanical Advantage

• What Is Mechanical Advantage?
• A machines mechanical advantage is the number of
  times the machine multiplies force.
• Calculating Mechanical Advantage You can find
  mechanical advantage by using the following
  equation

Mechanical advantage (MA) Output Force
Input Force
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Simple Machines
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What is a Simple Machine?

• A simple machine has few or no moving parts.
• Simple machines make work easier

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Wheels and Axles

• The wheel and axle are a simple machine
• The axle is a rod that goes through the wheel
  which allows the wheel to turn
• Gears are a form of wheels and axles

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Pulleys

• Pulley are wheels and axles with a groove around
  the outside
• A pulley needs a rope, chain or belt around the
  groove to make it do work

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Inclined Planes

• An inclined plane is a flat surface that is
  higher on one end
• Inclined planes make the work of moving things
  easier

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Wedges

• Two inclined planes joined back to back.
• Wedges are used to split things.

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Screws

• A screw is an inclined plane wrapped around a
  shaft or cylinder.
• The inclined plane allows the screw to move
  itself when rotated.

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Levers-First Class

• In a first class lever the fulcrum is in the
  middle and the load and effort is on either side
• Think of a see-saw

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Levers-Second Class

• In a second class lever the fulcrum is at the
  end, with the load in the middle
• Think of a wheelbarrow

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Levers-Third Class

• In a third class lever the fulcrum is again at
  the end, but the effort is in the middle
• Think of a pair of tweezers

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Simple Machines

• Simple Machines can be put together in different
  ways to make complex machinery