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NW C4 Simple Machines (p124-135) (levers (different types of levers-the…
NW C4 Simple Machines (p124-135)
Inclined plane
aka a ramp, which is a flat sloped surface
inclined planes allow you to input force over a bigger distance, so the input force becomes less then the output force
to find the mechanical advantage of the inclined plane - ideal mechanical advantage = length of incline/height of incline
wedge
thick at one end and thins down at the other end, ex-axe, zipper, knife
to use this simple machine you move the actual wedge, the input force is the handle and the blade is the output force(where it cuts)
ideal mechanical advantage = the length of the wedge/width of the wedge so the longer and thiner the wedge is the bigger mechanical advantage is
screws
a screw is an inclined plane that has been wrapped around a cylinder, ex-lightbulbs, bolts, jar lids
when the screw is twisted you exert a force into the screw which pulls the screw into the material and the friction holds the screw in place
if the threads of the screw are closer together the more time you have to turn the screw which is more of a mechanical advantage. ideal mechanical advantage = length of the threads of the screw/length of the screw(height of it)
levers
a lever is a rigid bar that can rotate/pivot on a fixed point(fulcrum)
one side is the input force where you put force like a handle the fulcrum is where the lever pivots and on another side there is the output force where something else is getting pushed or lifted
the ideal mechanical advantage = distance from fulcrum to input force/distance from fulcrum to output force
different types of levers-the fulcrum, input force and output force can be placed in different locations on different levers
first class lever
they change the direction of the input force. ex-scisiors, pliers, paint can opener and seesaws
second class lever
increases force bot don't change the direction. ex-doors, bottle openers and nutcrackers
third class lever
increases distance bout dosen't change the direction. ex-baseball bats, shovels, hockey sticks
wheel and axle
two cylindrical objects put together that rotate around a common. the larger radius object is the wheel and the smaller radius object is the axis. ex-car steering wheel, door knob
when you turn either one force is outputted in the other side. the wheel and axle increase force over a longer distance
the mechanical advantage = radius of wheel/radius of axle
pulley
a grooved wheel and a rope/cable wrapped around it. ex- flagpole
when you pull down one end(input force) the other side pulls up the object on the end of it(output force). pulleys decrease amount of input force and can change the direction of the input force.
types of pulleys-some are fixed and others are moveable.
fixed pulley
doesn't change the amount of force but changes the direction of the force
moveable pulley
decreases the input force that is needed but doesn't change the direction of the input force
block and tackle
is a pulley that has both movable pulleys and fixed pulleys
ideal mechanical advantage is equal to the number of sections of rope that support the object
compound machines
many machines are a combination of two or more simple machines which is then called a compound machine. the ideal mechanical advantage of a compound machine is the product ( x ) of each of the mechanical advantages of the simple machines.
ex-apple peeler which has a wedge, screw and a wheel and axle
simple machines in the body
levers
-most machines in your body are levers because muscles are attached to bones and joints which all move
wedges
- your front teeth(incisors) are wedges because they are sharp and when you bit something it is an edge which can break food into pieces