Simple Machines

What are the 6 simple machines?Inclined planeWedgeScrew LeverWheel & AxlePulley

MACHINEDef: A device that allows you to do work in a way that is easier.Sent.: They have agreed to rely primarily on the use of the six simple machines to accomplish their mission.

MACHINESp: mquinaDiscuss in your group different machines.

HOW DOES A MACHINE MAKE WORK EASIER?Change the amount of force you exertChange the distance over which you exert your force.Change the direction in which you exert your force.

INPUT FORCEDef.: The force exerted on a machine Sent.: Machines such as the car jack, the ramp, the crow bar, and the claw hammer make work easier by making the output force greater than the input force. Sp.: fuerza aplicada

OUTPUT FORCEDef.: The force exerted on an object by a machine.Sent.: Machines such as the car jack, the ramp, the crow bar, and the claw hammer make work easier by making the output force greater than the input force.Sp.: fuerza desarrollada

INPUT WORKDef.: The work done on a machine as the input force acts through the input distance.Sent.: For such an ideal machine, the input work would equal the output work. Sp.: trabajo aportado

OUTPUT WORKDef.: The work done by a machine as the output force acts through the output distance.Sent.: For such an ideal machine, the input work would equal the output work. Sp.: trabajo producido

MECHANICAL ADVANTAGEDef.: Number of times a machine increases a force exerted on it.Sent.: The mechanical advantage of a machine without friction is called the ideal mechanical advantage, or IMA. Sp.: ventaja mecnica

Mechanical Advantage = Output force Input force

If the machine increases force then the mechanical advantage will be greater than 1.

If the machine increases distance then the mechanical advantage will be less than 1.

If the machine changes the direction then the mechanical advantage will be 1.

Simple Machines

Inclined Plane

Inclined PlaneDef.: Flat, sloped surfaceSent.: An inclined plane allows you to exert your input force over a longer distance.Sp.: plano inclinadoDiscuss with your table different types of ramps.

Inclined PlaneHow it works: increases the distance the input force has to go.IMA = length of incline height of incline

Direct RelationshipDef.: When both variable either increase or decreaseSent.: Is the relationship direct or indirect?Sp.: relacin directa

Indirect RelationshipDef.: When one variable increases, the other decreasesSent.: Is the relationship direct or indirect?Sp.: relacin indirecta

Wedge

TaperDef.: to become smaller or thinner toward one end. .Sent.: A wedge is a device that is thick on one end and tapers to a thin edge on the other endSp.: disminucin graduaWhat are different things that taper?

WedgeDef.: a device that is thick on one end and tapers to a thin edge on the other end.Sent.: That force pushes the wedge down into the wood.Sp.: cuaWith your table make a list of at least 5 different wedges. Raise your hand when you have your list.

WedgeTwo inclined planes back to backHow it works: The wedge moves exerting an output force at a 90 angleIMA = length of wedge width of wedge

Screw

ThreadDef.: a helical groove in a cylindrical hole ( female thread ), formed by a tap or lathe tool, or a helical ridge on a cylindrical bar, rod, shank, etc ( male thread ), formed by a die or lathe tool Kid def.: A twisting raised area around a cylinder or inside a round hole.

ThreadSent.: Record the effort force, the distance lifted and the thread density for 5 tests Sp.: temaDiscussion: Is a screw with threads closer together have a higher or lower thread density?

ScrewDef.: An inclined plane wrapped around a cylinder creating spirals called threads.Sent.: Like a wedge, a screw is a simple machine that is related to the inclined plane.Sp.: tornilloDiscussion: Are there different types of screws? If so, what are they?

ScrewHow it works: Threads increase the distance over which you exert input force.The output force pulls the screw into the material. Friction holds it in place.IMA = length around the threads length of screw

Levers

LeverDef: A rigid bar that is free to pivot (rotate.)Kid Def.: A stiff bar that can rotate freelySent.: What are the advantages of using a lever to lift this stone? Sp.: palancaDisc.: What levers do you use every day?

FulcrumDef.: The fixed point that a lever pivots around.Sent.: Predict fulcrum placements which will not be successful. Sp.: fulcroDisc.: What types of things can be a fulcrum?

3 Types of Levers

1st Class LeverHow it works: Changes direction of input forceIf fulcrum is closer to output force, also increases force.If fulcrum is closer to input force, also increases distance.Calculating IMA:

1st Class Lever Ex. paint can opener, scissors

2nd Class LeverHow it works: Increases force but doesnt change direction.Calculating IMA:

2nd Class LeverEx.: Wheel barrow, doors, nutcrackers

3rd Class LeverHow it works: Increases distance but doesnt change direction.Calculating IMA:

3rd Class LeverEx. Hockey stick, shovel, fishing pole

Wheel & Axle

RadiusDef.: a straight line extending from the center of a circle or sphere to the circumference or surfaceSent.: As the radius of the wheel increases, what happens to its circumference? Sp.: radio

RegulateDef.: To controlor direct according to rule, principle, or law. Sent.: The crew's final task at this location is to construct a device to regulate the flow of water through the irrigation canals.Sp.: ajustar

Wheel & AxleDef.: Made of 2 circular/cylindrical objects fastened together that rotate around a common axis.Object with larger radius is wheel, and smaller radius is axle.

Wheel & AxleHow it works: Increases your force by going a longer distance.Calculating IMA: IMA = radius of wheel radius of axleEx.: door knob, car wheel & axle, steering wheel, windmill, water wheel

Wheel & Axle

Pulleys

PulleysDef.: A grooved wheel with a rope or cable wrapped around it.Sent.: As the number of supporting ropes on the pulley increases, what happens to the length of rope that must be pulled to lift the stone into place? Sp.: poleaDisc.: What pulleys have you seen?

PulleysHow it works: Pulling on rope (input force )causes an object to move up.It can decrease the amount of input force needed and it can change direction of input force.IMA = number of sections of rope that support object

Types of PulleysFixed How it works: changes direction of the forceDef.: Pulley is attached to an objectIMA = 1

Types of PulleysMovable How it works: decreases amount of input force needed, doesnt change directionPulley isnt attachedIMA = 2

Types of PulleysBlock and Tackle Def.: made of fixed and moveable pulleysHow it works: Decreases amount of input force neededIMA = 3

Compound MachinesDef.: A machine that utilizes two or more simple machines.IMA = product of the individual IMA of each simple machine that makes up compound machine.

Simple Machines in the BodyAt joints are levers - muscles are input force, and output force does the workTeeth are wedges