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30 Cards in this Set
- Front
- Back
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What is a machine?
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Any device that makes work easier.
Reminders: - Work is the transfer of energy. - Work can be thought of as the amount of energy required to move an object a certain distance with a specific force. |
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What are the six simple machines?
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- Wheel and axle
- Screw - Lever - Inclined plane - Pulley - Wedge |
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What are the three ways that machines can make work easier?
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1 - Changing the amount of force you exert.
2 - Changing the distance over which you exert the force. 3 - Changing the direction in which you exert the force. |
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True or false: In an ideal machine, the work into a machine should equal the work out of a machine.
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TRUE
However, in reality, the work out will always be less than work in. |
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Work out will always be less than work in due to _____________.
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FRICTION
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True or false: Scientists have succeeded in making the perfect, ideal machine.
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FALSE
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What are some examples of inclined planes?
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Ramps, slides, stairs
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What is an inclined plane?
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A flat surface that is higher on one end.
- Used to move objects to a higher or lower place. - Makes the work of moving things easier. |
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What is a screw?
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An inclined plain wrapped around a cylindrical post.
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How does a screw work?
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As the screw is turned, the inclined plain moves through the resistance. Thus, the load actually moves up the inclined plane.
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What is a wedge?
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Two inclined planes put together.
Instead of the load moving, the wedge moves. The resistance does not move up the inclinde plane, but rather the inclined plane moves through the resistance. |
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What is a pulley?
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A rope, chain, or belt wrapped around a grooved wheel (also known as a fulcrum).
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True or false: A pulley is actually a type of lever.
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TRUE
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What are the two types of pulleys?
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Fixed pulley - The load is attached to one end of the pulley rope, and the pulley itself is attached to something that does not move.
Moveable pulley - The load is attached to the pulley intself and the ropes allow the entire pulley to move. |
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True or false: Fixed pulleys do not change the direction of force.
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FALSE
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What is a wheel and axle?
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A simple machine made up of two wheels of different sizes that rotate together.
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True or false: A wheel is a modified lever.
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TRUE
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True or false: A wheel and axle cannot overcome friction.
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FALSE
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What is a lever?
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A rigid bar that is free to move about a fixed point.
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What are some examples of levers?
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- See-saw
- Hammer - Spoon - Hockey stick |
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What are the parts of a lever?
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Fulcrum - fixed point around which a lever pivots
Effort Arm - The part of the lever that the effort force is applied to Resistance Arm - The part of the lever that applies the resistance force. |
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What is a compound machine?
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Any device made up of two or more simple machines.
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Examples of compound machines are…
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- Pencil sharpener
- Computer - Bicycle |
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What is a "Rube Goldberg device"?
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A compound machine that performs a very simple task in a very difficult way, through a series of energy conversions between simple machines.
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What is an example of a "Rube Goldberg device"?
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The game "mousetrap"
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Draw a lever and label its parts.
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Do this on a piece of paper and compare it to the slide in the Machines notes.
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What is a first class lever?
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The fulcrum is located between the resistance arm and the effort arm.
Examples: See-saw, scissors. |
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What is the difference between the three classes of levers?
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The location of the fulcrum relative to the resistance and effort arm.
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What is a second-class lever?
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The resistance artm is located between the effort force and the fulcrum.
Examples: Wheelbarrow, bottle opener. |
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What is a third-class lever?
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The effort force is located between the fulcrum and the resistance.
Examples: Rake, shovel, baseball bat. |
