 | Term | Definition |
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six types of simple machines: |
pulley, wheel and axle, wedge, inclined plane, screw, and lever |
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inclined plane |
a flat sloped surface |
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how does an inclined plane make work easier? |
it allows you to exert your input force over a longer distance so then you dont need to use as much force. |
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how do you find the ideal mechanical advantage of an inclined plane? |
divide the length of the incline by the height |
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example of an inclined plane |
ramp |
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wedge |
a device that is thick at one end and tappers to a thin edge at the other end |
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examples of a wedge |
sand wedge, door stop, axe, stoppers |
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how is a wedge like an inclined plane? |
it is like an inclined plane (or sometimes two inclined planes back to back) that can move |
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mechanical advantage of a wedge |
divide the length of the wedge by the height |
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screw |
can be thought of as an inclined plane wrapped around a cylinder |
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examples of a screw |
bolt, drill (auger), bottle cap |
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how is a screw like an inclined plane? |
the threads of a screw act like an inclined plane to increase the distance over which you exert the input force |
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mechnical advantage of a screw |
the length around the threads divided by the length of the screw |
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when does a screw have a lot of mechanical advantage |
the closer together the threads of the scrw are, the greater mechanical advantage |
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the length around the threads of a screw is the same as |
the length of an inclined plane |
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lever |
a rigid bar that is free to pivot or rotate on a fixed point |
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fulcrum |
the fixed point that a lever pivots on |
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ideal mechanical advantage of a lever |
divide the distance from the fulcrum to the input force by the distance from the fulcrum to the output force |
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how many types of levers are there? |
three |
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first class levers make work easier by |
changing the direction of the input force |
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second class levers make work easier by |
increaseing force, but not changing direction |
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third class levers make work easier by |
increasing distance, but not changing the direction |
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where is the fulcrum located on a first class lever? |
picture |
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where is the fulcrum located on a second class lever? |
picture |
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where is the fulcrum located on a third class lever? |
picture |
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examples of a first class lever |
scissors, pilers, and seesaws |
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examples of a second class lever |
doors, nutcrackers, and bottle openers |
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examples of a third class lever |
fishing poles, shovels, and baseballs |
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what has the bigger radius in a wheel and axle? |
the wheel |
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how do you find the mechanical advantage of a wheel and axle? |
by dividing the raidus of the wheel by the raidus of the axle |
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a simple machine made up of a grooved wheel with a rope or cable wrapped around it |
pulley |
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how many types of basic pulleys are there |
two |
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fixed pulley |
a pulley that is attached to a strucutre |
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moveable pulley |
a pulley that is attached to the object you wish to move |
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what are the basic types of pulleys |
moveable and fixed |
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the ideal mechanical advantage of a pulley is equal to |
the number of sections of rope that support the object |
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what are some examples of a lever? |
crowbar, back of a hammer, and a seesaw |
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what are some examples of a pulley? |
flag pole, weight machine |
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what are some examples of a wheel and axle? |
gears, hoe, cars, line painter, water wheel, wheel barow, and door knob. |
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our body is filled with |
simple machines |
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what is the machine most of our body is made up of |
levers |
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what do our front teeth resemble |
wedges |
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complex machine |
a machine that utilizes two or more simple machines |
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what body parts act as the fulcrum |
joints |
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in a wheel and axle, what happens to the output force when the input force is applied to the wheel? |
the axle exerts a large output force (increases force) |
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in a wheel and axle, what happens to the output force when the input force is applied to the axle? |
the wheel exerts an output force less then the input force (increases distance) |
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wheel and axle |
a simple machine made of two circular or cylindrical objects fastend together that rotate about a ccommon axis. |
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examples of a complex machine |
shovel-wedge and lever, can opener-wedge, lever, and wheel & axle |
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first class lever in your body |
the joint at the top of your neck is the fulcrum of a first class lever. the muscles in the back of yourneck provide the input force. the output force is used to tilt your head back. |
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second class lever in your body |
the ball of your foot is the fulcrum of a second class lever. the muscle in the calf of your leg provides the input force. the output force is used to raise your body. |
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third class lever in your body |
your elbow is the fulcrum of a third class lever. your biceps muscle provides theinput force. the output force is used to lift your arm. |
