2WHAT IS WORK? WORK = FORCE X DISTANCE Joules = newtons (N) X meters (m)
3CALCULATING WORK ----------------------------------------------- The crane uses 30 newtons of force to lift the iron block 8 meters.Work done = Force x Distance moved = 30 newtons (F) x 8 meters (D) = 240 JoulesHow much work was done?Because the block is held up high, it becomes: potential energy= 240 J (due to gravity)If the mass then falls freely to the ground, just before it hits the ground, it’s . . .240 J of kinetic energy
5Longer Plane = More Distance INCLINED PLANEFlat surface with 1 end higher than otherUsed to gradually raise or lower objectsEFFICIENCYFriction reduced if surfaces of plane & load are smoothMECHANICAL ADVANTAGE (MA)INPUT FORCEDISTANCELonger Plane = More Distance
7Longer Point/Edge = More Distance WEDGEType of inclined planeHas 1 or 2 sloping sidesForce applied to wide endNarrow end driven into object– push object apartEFFICIENCYFriction reduced if edge sharperMECHANICAL ADVANTAGE (MA)INPUT FORCEDISTANCELonger Point/Edge = More Distance
9More threads = More Distance SCREWType of inclined planeWrapped around a rodDirection of force changedAmount of force increasedEFFICIENCYIncreased when threads closerMECHANICAL ADVANTAGE (MA)INPUT FORCEDISTANCEMore threads = More Distance
11LEVER Does work by turning around FULCRUM (fixed point) Force applied to do the work = EFFORTForce created by LOAD when trying to move it = RESISTANCEEFFICIENCY GREATEST WHEN WORK REQUIRES THE LEAST EFFORT
12Longer Effort Arm = More Distance MECHANICAL ADVANTAGE (MA)INPUT FORCEDISTANCELonger Effort Arm = More Distanceeffort armloadeffortfulcrum
13LESS EFFORT NEEDED TO DO THE WORK LESS DISTANCE BETWEEN LOAD & FULCRUMLESS EFFORT NEEDED TO DO THE WORK
21Summary of LEVER CLASSES 1st Class 2nd Class 3rd ClassBy whether the fulcrum, load, or effort is in the center.How do you know what class a lever is?Fulcrum= Pivot Point Effort force = input forceLoad (Resistance) = output force
22Turning larger wheel = More Distance WHEEL & AXLELarge wheel fixed to smaller wheel (or shaft) called an axleBoth turn togetherEffort usually on larger wheel, moving load of axleMECHANICAL ADVANTAGE (MA)INPUT FORCEDISTANCETurning larger wheel = More Distance
23Think of as lever rotating in circle around center fulcrum Like steering wheel (larger wheel) on column (axle)Wheel & axle turn togetherEFFICIENCY:Reduced friction with lubricant
29GEARS Wheels with teeth, so one turns the next SMALLER gear turns FASTER than larger gearOne gear makes other gear beside it turn in OPPOSITE DIRECTIONSpeeds things up,slows them down, changes direction of forceGEARS
30Compound machines are made of 2 or more simple machines.
31Illustrating… COMPOUND MACHINES Made of at Least 2 SIMPLE MACHINES KIDS’ INVENTIONSIllustrating…COMPOUND MACHINES Made of at Least 2 SIMPLE MACHINES
32This is the Chore 3,000.He can clean your room. It can take the trash out and do other chores. He is made of gears, screws and pulleys..
33This simple machine is The Kids’ Chore. 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, it will dust anything for you. The simple machines we used were the wheel and axle,inclined plane, just wheels, pulleys, and gears.
34This is the Chore 5,000.He can clean your room. It can take the trash out and do other chores. He is made of gears, screws and pulleys.