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GRADE 6GRADE 6GRADE 6GRADE 6Mrs. Mrs. FigotenFigoten
WORK & SIMPLEWORK & SIMPLE MACHINES MACHINES
WORKWORK = = FORCEFORCE X X DISTANCEDISTANCE
JoulesJoules = = newtons (N) newtons (N) X X meters (m)meters (m)
WorkWork done done = = FForce x orce x DDistance movedistance moved = 30 = 30 newtonsnewtons (F)(F) x 8 x 8 metersmeters (D)(D) = 240 = 240 JoulesJoules
Because the block is held up high, it Because the block is held up high, it becomes: becomes: potentialpotential energy energy = 240= 240 JJ (due to gravity(due to gravity)
If the mass then falls freely to the ground,If the mass then falls freely to the ground, just before it hits the ground, it’s just before it hits the ground, it’s . . . . . .
240240 JJ of of kinetickinetic energy energy
CALCULATING WORKCALCULATING WORKThe crane uses 30 newtons of force to lift the iron block 8 meters.The crane uses 30 newtons of force to lift the iron block 8 meters.
----------------------------------------------------------------------------------------------How much work was done?How much work was done?
INCLINED PLANEINCLINED PLANE Flat surface with 1 end higher than otherFlat surface with 1 end higher than other
Used to gradually raise or lower objectsUsed to gradually raise or lower objects
EFFICIENCYEFFICIENCY Friction reduced if surfacesFriction reduced if surfaces
of plane & load are smooth of plane & load are smooth
MECHANICAL ADVANTAGEMECHANICAL ADVANTAGE (MA) (MA)
INPUTINPUT FORCE FORCE DISTANCEDISTANCE
Longer PlaneLonger Plane = More Distance = More Distance
Examples ofExamples ofINCLINED INCLINED PLANESPLANES
http://www.smartown.com/sp2000/machines2000/inclinedplane.htm
WEDGEWEDGE Type of inclined planeType of inclined plane Has 1 or 2 sloping sidesHas 1 or 2 sloping sides Force applied to wide endForce applied to wide end Narrow end driven into object– push object Narrow end driven into object– push object
apartapart
EFFICIENCYEFFICIENCY Friction reduced if edge sharperFriction reduced if edge sharper
MECHANICAL ADVANTAGEMECHANICAL ADVANTAGE (MA)(MA)
INPUTINPUT FORCE FORCE DISTANCEDISTANCE
Longer Point/EdgeLonger Point/Edge = More Distance = More Distance
Examples of WEDGES
SCREWSCREW Type of inclined planeType of inclined plane
Wrapped around a rodWrapped around a rod Direction of force changedDirection of force changed Amount of force increasedAmount of force increased
EFFICIENCYEFFICIENCY Increased when threads closerIncreased when threads closer
MECHANICAL ADVANTAGEMECHANICAL ADVANTAGE (MA)(MA)
INPUTINPUT FORCE FORCE DISTANCEDISTANCE
More threadsMore threads = More Distance = More Distance
Examples ofSCREWS
LEVER Does work by turning around
FULCRUM (fixed point) Force applied to do the work =
EFFORT Force created by LOAD when trying
to move it = RESISTANCE
EFFICIENCY GREATESTWHEN WORK REQUIRESTHE LEAST EFFORT
MECHANICAL ADVANTAGE (MA)MECHANICAL ADVANTAGE (MA)
INPUTINPUT FORCE FORCE DISTANCEDISTANCE
Longer Effort ArmLonger Effort Arm = More Distance = More Distance
loadload
efforteffort
fulcrumfulcrum
effort arm
effort arm
LESS EFFORT NEEDEDTO DO THE WORK
LESS DISTANCE BETWEEN
LOAD & FULCRUM
TYPES OF LEVERS
FIRST CLASS LEVER
SECOND CLASS LEVER
THIRD CLASS LEVER
Summary of LEVER CLASSES
1st Class 2nd Class 3rd Class
Fulcrum= Pivot Point
Effort force = input force
Load (Resistance) = output
force
By whether the fulcrum, load, or effort is in the center.
How do you know what class a lever is?
WHEEL & AXLE Large wheel fixed to smaller wheel (or shaft)
called an axle
Both turn together
Effort usually on larger wheel, moving load of axle
MECHANICAL ADVANTAGEMECHANICAL ADVANTAGE (MA)(MA)
INPUTINPUT FORCE FORCE DISTANCEDISTANCE
Turning Turning larger wheellarger wheel = More Distance = More Distance
Think of as lever Think of as lever rotating in circlerotating in circle around center fulcrumaround center fulcrumLike steering wheel (larger wheel) on
column (axle)Wheel & axle turn together
EFFICIENCY:EFFICIENCY: Reduced friction with lubricant
HOW DOES WHEEL & AXLE WORK?
PULLEYWheel with groove Allows rope to ride on wheel
without slipping off
MECHANICAL ADVANTAGEMECHANICAL ADVANTAGE (MA)(MA)
INPUTINPUT FORCE FORCE DISTANCEDISTANCE
Rope around Rope around more wheelsmore wheels = More Distance = More Distance
TYPES OF PULLEYS
FIXED PULLEY (like clothesline or flagpole)
Pulley stays in one position
Moves LOAD up, down or sideways
Changes DIRECTION of force
Does not reduce EFFORT
TYPES OF PULLEYS
MOVABLE PULLEY(for lifting or lowering heavy objects)
Moves along with LOAD
Reduces EFFORT
Increases DISTANCE
Examples ofPULLEYS
GEARS
Wheels with teeth, so one turns the next SMALLER gear turns FASTER than larger gear One gear makes other gear beside it turn in
OPPOSITE DIRECTION Speeds things up,slows them down, changes
direction of force
COMPOUND MACHINE
Compound machines are made of 2 or more
simple machines.
KIDS’ INVENTIONS
Illustrating… COMPOUND MACHINES Made of
at Least 2 SIMPLE MACHINES
He can clean your room. It can take the trash out and do other chores. He is made of gears, screws and pulleys..
This is the Chore 3,000.
Our simple machine does a lot of stuff such as recycles cans and then washes them, and then has them come to be used again. Another thing it does is washes clothes and hangs them back up for kids.
It also cooks popcorn and pours drinks.Another thing it does is dusting, itwill dust anything for you. The simplemachines we used were the wheeland axle,inclined plane, just wheels,pulleys, and gears.
This simple machine is The Kids’ Chore.
He can clean your room. It can take the trash out and do other chores. He is made of gears, screws and pulleys.
This is the Chore 5,000.