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Published byMarshall Preacher Modified about 1 year ago

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LESSON 1: WORK, ENERGY AND POWER WORK: THE USE OF FORCE TO MOVE AN OBJECT BOTH FORCE & MOTION MUST BE IN THE SAME DIRECTION EQUATION: WORK = FORCE x DISTANCE UNITS OF WORK : 1 NEWTON * 1 METER = 1 JOULE (1 Nm)

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ENERGY: THE ABILITY TO DO WORK ENERGY IS NECESSARY TO DO WORK UNITS OF ENERGY – SAME AS UNIT OF WORK : JOULES (j) WORK TRANSFERS ENERGY TO AN OBJECT POWER: HOW FAST WORK IS DONE EQUATION: ENERGY ÷ TIME UNITS OF POWER: JOULE PER SECOND (JOULE/SEC) = 1 WATT NAMED AFTER JAMES WATT (STEAM ENGINES, 1800’S) 1 HORSEPOWER = 746 WATTS

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LESSON 2: KINETIC AND POTENTIAL ENERGY KINETIC ENERGY (KE): THE ENERGY OF MOTION (measured in joules) ALL MOVING OBJECTS OR MOLECULES HAVE KINETIC ENERGY KINETIC ENERGY DEPENDS ON MASS AND SPEED EQUATION: ½ mv 3

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3 POTENTIAL ENERGY (PE): STORED ENERGY (measured in joules) POTENTIAL ENERGY HAS THE ABILITY TO DO WORK TYPES OF POTENTIAL ENERGY GRAVITATION POTENTIAL ENERGY BASED ON HEIGHT GPE = mass x 9.8 m/s 2 x height (gpe = m*g*h) GREATER HEIGHTS RESULT IN GREATER gpe. ELASTIC POTENTIAL ENERGY STORED IN STRETCHED OBJECT MECHANICAL POTENTIAL (ME) STORED IN POSITION NOT HEIGHT ABOVE GROUND (gpe) EQUATION: ME = KE + PE CHEMICAL POTENTIAL STORE IN BONDS BETWEEN ATOMS

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MACHINES: DEVICES THAT MAKE WORK EASIER MACHINES CAN CHANGE SIZE OF FORCE, DIRECTION OF FORCE, & DISTANCE OF FORCE SIMPLE MACHINES MAKE UP MACHINES SIMPLE MACHINES MAKE WORK EASIER WITH A SIMPLE MOTION 6 SIMPLE MACHINES: RAMPS, LEVERS. WHEELS/AXLES, SCREW, WEDGES, PULLEYS MACHINES CAN MULTIPLE FORCE OR MULTIPLE DISTANCE CANNOT DO BOTH AT THE SAME TIME FORCE MULTIPLIED FORCE AT THE COST OF LONGER DISTANCES DISTANCE MULTIPLIED AT THE COST OF GREATER FORCES CAN NEVER MULTIPLY WORK

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MECHANICAL ADVANTAGE: INDICATES HOW FORCE (OR DISTANCE) IS MULTIPLIED MA = 1: DISTANCE MULTIPLIED MA > 1 FORCE MULTIPLIED MA < 1 DISTANCE MULTIPLIED MA EQUATION: MA = OUTPUT FORCE ÷ INPUT FORCE OUTPUT FORCE: FORCE DONE BY THE MACHINE INPUT FORCE: FORCE YOU PUT INTO MACHINE

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MECHANICAL EFFICIENCY: INDICATES HOW MUCH WORK IS LOST TO FRICTION ME IS ALWAYS A PERCENTAGE LESS THAN 100% (FRICTION ALWAYS PRESENT) ME EQUATION: ME = (WORK OUTPUT ÷ WORK INPUT ) x 100 WORK OUTPUT: WORK DONE BY THE MACHINE WORK INPUT: WORK YOU PUT INTO A MACHINE

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THE 6 TYPES OF SIMPLE MACHINES 1. LEVER: A BAR THAT PIVOTS ON A FULCRUM (THE PIVOT POINT OF A LEVER) 1 ST CLASS LEVER: FULCRUM IN MIDDLE (“F”) MULTIPLES FORCE OR DIRECTION AND CHANGES DIRECTION EXAMPLE: SEE-SAW 2 ND CLASS LEVER: RESISTANCE (OBJECT) IN THE MIDDLE (“R”) MULTIPLES FORCE WITHOUT CHANGING DIRECTION EXAMPLE : WHEEL BARROW, RAKES 3 RD CLASS LEVER: EFFORT IN THE MIDDLE – YOU – (“E”) MULTIPLIES DISTANCE WITHOUT CHANGING DIRECTION USED TO MULTIPLE THE MOMENTUM TRANSFERRED TO OBJECTS IN SPORTS EXAMPLES: BASEBALL BATS, GOLF CLUBS, HAMMERS

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3. WHEEL AND AXLE: A LARGER WHEEL THAT TURNS A SMALLER SHAFT MA OF A WHEEL & AXLE THE RESULT OF THE THEIR SIZE DIFFERENCE MA = RADIUS OF INPUT (WHEEL) ÷ RADIUS OF OUTPUT (SHAFT) LARGER WHEELS CREATE GREATER MA 4. INCLINED PLANES: A SLANTED, FLAT SURFACE ( A RAMP ) LONGER RAMPS HAVE A GREATER IDEAL MA LESS FORCE BUT LONGER DISTANCES FRICTION REDUCES THE ACTUAL MA OF RAMPS IDEAL MA OF A RAMP = RAMP LENGTH ÷ RAMP HEIGHT

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5. WEDGES: A MOVABLE SINGLE OR DOUBLE INCLINED PLANE LONGER, THINNER WEDGES HAVE GREATER IDEAL MA EXAMPLES: HAMMER CLAW, CHISEL, KNIFE EDGE 6. SCREW: AN INCLINED PLANE WRAPPED AROUND A CYLINDER THREADS: THE TERM FOR THE RIDGES ON A SCREW CLOSER THREADS HAVE GREATER IDEAL MA

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3. PULLEYS: A GROOVED WHEEL AND AXLE HOLDING A LINE OR ROPE IDEAL MA OF A PULLEY SYSTEM EQUALS THE # OF LINES HOLDING UP OBJECT FIXED PULLEYS: ATTACHED TO A STATIONARY OBJECT: CANNOT MOVE CAN ONLY CHANGE THE DIRECTION OF FORCE ALWAYS HAVE AN IDEAL MA OF 1 MOVABLE PULLEY: NOT ATTACHED, FREE TO MOVE UP AND DOWN MOVING PULLEYS DO NOT CHANGE THE DIRECT OF FORCE MOVING PULLEYS MULTIPLY FORCE AT THE COST OF LONGER DISTANCES PULLEY SYSTEMS (BLOCK AND TACKLES) COMBINE FIXED AND MOVING PULLEYS PULLEY SYSTEMS MAY BOTH CHANGE DIRECT OF FORCE AND MULTIPLY FORCE PULLEY SYSTEMS MULT. FORCE: MA = # OF LINES HOLDING MOVABLE PULLEY

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COMPOUND MACHINES: A COMBINATION OF SIMPLE MACHINES TOTAL IDEAL MA : PRODUCT OF ALL SIMPLE MACHINES. WHICH MAKE IT UP GEAR SYSTEM: AN EXAMPLE OF A COMPOUND MACHINE SIMPLE MACHINES IN THE HUMAN BODY FOREARM: EXAMPLE OF 3RD CLASS LEVER BALL OF FOOT: A 2ND CLASS LEVER NECK: A FIRST CLASS LEVER INCISORS: TEETH WHICH FUNCTION AS WEDGES

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ROSIE, IRON WORKERS, WELDER, MIGRANT WORKERS, SINGER MACHINE, SIMPLE MACHINES, BIKE, INPUT/OUTPUT, Effort/load, See/saw, Pulley, SIMPLE MACHINES, INCLINED PLANE: SCREW:http://discover.edventures.com/images/termlib/s/screw/support.gifhttp://discover.edventures.com/images/termlib/s/screw/support.gif LEVER: PULLEY: WHEEL: ROTATE LEVER: LEVERS: WEDGE: SCREWS: TRUCK RAMP: SCREWS: SISSORS:

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