work and machines

simple machines

the most basic devices for making work easier

which tools are in the inclined plane family

the inclined plane, the wedge, and the screw

inclined plane

a flat, sloped surface

what do inclined planes allow you to do

they allow you to exert your input force over a longer distance

how to determine ideal mechanical advantage of an inclined plane

divide the length of the incline by its height

wedge

a device that is thick at one end and tapers to a thin edge at the other

how to use a wedge

move the inclined plane instead of moving the object along it

how to find ideal mechanical advantage of a wedge

divide its length by its width

screw

inclined plane wrapped around a cylinder

how do screws work

its threads act like an inclined plane to increase the distance over which you exert the input force

how to find ideal mechanical advantage of a screw

the length around the threads divided by the length of the screw

lever

a rigid bar that is free to rotate or pivot

fulcrum

the fixed point that a lever pivots around

how to find the ideal mechanical advantage of a lever

distance from fulcrum to input force/distance from fulcrum to output force

first class levers

change the direction of the input force, increase force or distance, fulcrum between load and effort

second class levers

increase force but don't change its direction, the load is between the fulcrum and the input force

third class levers

increase distance, but do not change the direction of the input force, load begins after the fulcrum