1 / 46

SIMPLE MACHINES

SIMPLE MACHINES. 6 TYPES OF SIMPLE MACHINES. LEVER INCLINED PLANE PULLEY WEDGE SCREW WHEEL AND AXLE. MECHANICAL ADVANTAGE. THE MECHANICAL ADVANTAGE OF A SIMPLE MACHINE IS THE NUMBER OF TIMES THE MACHINE MULTIPLIES THE FORCE PUT IN OR THE SPEED OF THE FORCE PUT IN

lerato
Download Presentation

SIMPLE MACHINES

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. SIMPLE MACHINES Created by C. Douglas 04-05

  2. 6 TYPES OF SIMPLE MACHINES • LEVER • INCLINED PLANE • PULLEY • WEDGE • SCREW • WHEEL AND AXLE Created by C. Douglas 04-05

  3. MECHANICAL ADVANTAGE • THE MECHANICAL ADVANTAGE OF A SIMPLE MACHINE IS THE NUMBER OF TIMES THE MACHINE MULTIPLIES THE FORCE PUT IN OR THE SPEED OF THE FORCE PUT IN • THERE ARE TWO TYPES OF MECHANICAL ADVANTAGE … IMA OR IDEAL MECHANICAL ADVANTAGE • AND AMA OR ACTUAL MECHANICAL ADVANTAGE • IMA IS IF THE MACHINE WERE PERFECT AND AMA IS WHAT REALLY HAPPENS Created by C. Douglas 04-05

  4. EFFORT FORCE (E) RESISTANCE FORCE (R) EFFORT DISTANCE (De) RESISTANCE DISTANCE (Dr) JOULE UNIT OF WORK ( A NEWTON METER WATT A UNIT OF POWER A JOULE PER SECOND WORK F x D POWERW T EFFICIENCY W(in) W(out) WORK(IN) = E x De WORK(out) = R x Dr ACTUAL MECHANICAL ADVANTAGE AMA = R / E IDEAL MECHANICAL ADVANTAGE IMA = De / Dr SIMPLE MACHINE TERMS Created by C. Douglas 04-05

  5. INCLINED PLANE • AN INCLINED PLANE IS A RAMP THAT WORKS BY SUPPORTING SOME OF THE LOAD, MAKING THE EFFORT LESS THAN IF YOU LIFTED THE ENTIRE LOAD STRAIGHT UP. HOWEVER, YOU MUST MOVE THROUGH A GREATER DISTANCE AND DO MORE WORK. THE STEEPER THE RAMP, THE LESS YOUR EFFORT IS MULTIPLIED. INCLINED PLANES MULTIPLY FORCE BUT DO NOT CHANGE ITS DIRECTION Created by C. Douglas 04-05

  6. FORCE NEEDED TO LIFT THE BOX IS EQUAL TO THE WEIGHT OF THE BOX IF THE BOX WEIGHS 200 POUNDS YOU NEED TO EXERT A 200 POUND FORCE TO LIFT IT. IN METRIC UNITS 200 POUNDS IS ABOUT 800 NEWTONS Created by C. Douglas 04-05

  7. RESISTANCE 200 LBS INCLINED PLANE THE FORCE REQUIRED TO SLIDE THE 200 POUND BOX UP THE INCLINED PLANE IS LESS THAN 200 POUNDS EFFORT FORCE 75 POUNDS Created by C. Douglas 04-05

  8. INCLINED PLANE MEASUREMENTS WE NEED TO DO INCLINED PLANE PROBLEMS EFFORT (E)POUNDS OR NEWTONS HEIGHT (Dr) RESISTANCE (R) POUNDS OR NEWTONS LENGTH DeFEET OR METERS Created by C. Douglas 04-05

  9. INCLINED PLANE EFFORT RESISTANCE HEIGHT (Dr) LENGTH (De) Created by C. Douglas 04-05

  10. THE STEEPER THE INCLINE, THE GREATER THE EFFORT FORCE REQUIRED TO RAISE THE RESISTANCE Created by C. Douglas 04-05

  11. INCLINED PLANE EFFORT 150 POUNDS RESISTANCE 200 POUNDS LENGTH (De) HEIGHT (Dr) Created by C. Douglas 04-05

  12. AMA = R/E AMA = 300N / 100N AMA = 3 IMA = De/Dr IMA = 8m/2m IMA = 4 EFFORT = 100 N EFFICIENCY = AMA/IMA*100 EFFICIENCY = 3/4*100 EFFICIENCY = 0.75 * 100 EFFICIENCY = 75% RESISTANCE = 300 N W(in) = E X De W(in) = 100N X 8 M W(in) = 800 JOULES Dr =2 m De = 8 m W(out) = R X Dr W(out) = 300N X 2 m W(out) = 600 JOULES Created by C. Douglas 04-05

  13. PRACTICE PROBLEM • SOLVE THIS PROBLEM BE SURE TO LIST ALL INFORMATION AND ALL FORMULAS THAT YOU USE • YOU NEED TO GET De, Dr, E, AND R Created by C. Douglas 04-05

  14. FIND IMA, AMA, EFFICIENCY, WORK(in) AND WORK(out) FORMULAS: IMA = De/Dr AMA = R/E EFFIC = AMA/IMA*100 WORK(in) = E X De WORK(out) = R X Dr E = 200 N R = 1000 N De = 14 m Dr = 2 m Created by C. Douglas 04-05

  15. PARTS OF A LEVER • RIGID BAR • FULCRUM Created by C. Douglas 04-05

  16. IN A LEVER, THE RIGID BAR ROTATES AROUND THE FULCRUM. THERE ARE 3 CLASSES OF LEVERS, ACCORDING TO WHERE THE EFFORT, RESISTANCE AND FULCRUM ARE LOCATED 1ST CLASS LEVER FULCRUM BETWEEN EFFORT AND RESISTANCE 2ND CLASS LEVER RESISTANCE IS BETWEEN EFFORT AND FULCRUM 3RD CLASS LEVER EFFORT IS BETWEEN RESISTANCE AND FULCRUM Created by C. Douglas 04-05

  17. 1ST CLASS (RFE) 2ND CLASS (FRE) 3RD CLASS (FER) Created by C. Douglas 04-05

  18. MEMORY TRICK FOR LEVERS • REMEMBER FRE 123(PRONOUNCE IT FREE ONE TWO THREE) • 1ST CLASS LEVER FULCRUM IN MIDDLE BETWEEN R AND E • 2ND CLASS LEVER RESISTANCE BETWEEN E AND F • 3RD CLASS LEVER EFFORT BETWEEN R AND F Created by C. Douglas 04-05

  19. LEVERS • LEVERS MAY MULTIPLY FORCE OR SPEED AND MAY CHANGE THE DIRECTION OF A FORCE. THEY CANNOT DO ALL THREE THINGS AT THE SAME TIME Created by C. Douglas 04-05

  20. EFFORT FORCE 1ST CLASS LEVER MAY MULTIPLY FORCE OR SPEED AND CHANGE DIRECTION OF FORCE Created by C. Douglas 04-05

  21. 1ST CLASS LEVERS • 1ST CLASS LEVERS CAN DO IT ALL, BUT ONLY TWO THINGS AT A TIME • THEY CAN MULTIPLY FORCE OR SPEED AND THEY CHANGE THE DIRECTION OF YOUR FORCE • YOU PUSH DOWN AND THE LOAD GOES UP • IF THE FULCRUM IS CLOSER TO THE LOAD (R) IT MULTIPLIES FORCE IF CLOSER TO THE E, MULTIPLIES SPEED • THINK ABOUT HOW YOU USE A LaCROSSE STICK Created by C. Douglas 04-05

  22. Created by C. Douglas 04-05

  23. YOUR OTHER HAND IS THE FULCRUM FORCE Created by C. Douglas 04-05

  24. EFFORT FORCE FULCRUM 2ND CLASS LEVER MAY MULTIPLY FORCE BUT NOT CHANGE DIRECTION OF FORCE OR MULTIPLY SPEED Created by C. Douglas 04-05

  25. A PRY BAR IS A 2ND CLASS LEVER Created by C. Douglas 04-05

  26. EFFORT FORCE FULCRUM 3RD CLASS LEVER MULTIPLIES SPEED BUT NOT FORCE. DOES NOT CHANGE DIRECTION OF FORCE Created by C. Douglas 04-05

  27. BASEBALL BATS AND GOLF CLUBSARE 3RD CLASS LEVERS Created by C. Douglas 04-05

  28. TYPICAL LEVER PROBLEMS • WHICH CLASS OF LEVER IS IT? • IF THE EFFORT FORCE ON A LEVER IS 100 NEWTONS AND THE RESISTANCE LIFTED IS 400 NEWTONS, WHAT WAS THE MECHANICAL ADVANTAGE • IF THE MECH ADV OF A LEVER IS 6, WHAT RESISTANCE MAY BE LIFTED WITH AN EFFORT FORCE OF 250 NEWTONS? Created by C. Douglas 04-05

  29. WEDGE • A WEDGE IS BACK TO BACK INCLINED PLANES • A FORCE APPLIED TO THE BACK OF THE WEDGE IS MULTIPLIED AND REDIRECTED TO THE SIDES • AN EXAMPLE OF A WEDGE IS A KNIFE BLADE, OR AN AXE HEAD Created by C. Douglas 04-05

  30. FORCE A WEDGE IS BACK TO BACK INCLINED PLANES. THE FORCE APPLIED TO THE FLAT BOTTOM IS FOCUSED AT THE TIP AND DIRECTED OUTWARD Created by C. Douglas 04-05

  31. WEDGE Created by C. Douglas 04-05

  32. A PULLEY IS A GROOVED WHEEL THAT SPINS FREELY AROUND ITS AXLE. A ROPE IS RUN THROUGH THE GROOVE. PULLEYS CAN CHANGE DIRECTION OF FORCE AND MULTIPLY FORCE. PULLEYS WORK BY DIVIDING FORCE BETWEEN STRANDS OF ROPE Created by C. Douglas 04-05

  33. RESISTANCE FORCE EFFORT FORCE PULLEY Created by C. Douglas 04-05

  34. PULLEY • PULLEYS MAY BE ATTACHED TO SOMETHING SOLID CALLED FIXED PULLEYS OR ATTACHED TO THE RESISTANCE (CALLED MOVEABLE PULLEYS) • THE MORE FIXED AND MOVABLE PULLEYS YOU USE IN A SET UP THE MORE YOUR FORCE IS MULTIPLIED Created by C. Douglas 04-05

  35. FIXED PULLEY EFFORT MOVEABLE PULLEY RESISTANCE RESISTANCE Created by C. Douglas 04-05

  36. FIXED PULLEY MOVEABLE PULLEY RESISTANCE Created by C. Douglas 04-05

  37. TO FIND THE IMA OF A PULLEY SYSTEM, COUNT THE NUMBER OF STRANDS OF ROPE IF THE STRAND YOU PULL ON IS PULLINGDOWN THEN DON’T COUNT IT IN THIS SYSTEM THERE ARE 3 STRANDS OF ROPE BUT THE LAST STRAND IS PULLING DOWN SO IT DOESN’T COUNT THE IMA = 2 2 3 1 R = 600 N Created by C. Douglas 04-05

  38. TO FIND THE AMA OF THE SYSTEM, AS ALWAYS, IT IS THE RESISTANCE DIVIDED BY THE EFFORT 2 3 1 EFFORT = 400 N AMA = R / E AMA = 6OO N / 400 N AMA = 1.67 R = 600 N Created by C. Douglas 04-05

  39. WHEEL &AXLE RESISTANCE FORCE EFFORT FORCE Created by C. Douglas 04-05

  40. EFFORT FORCE Effort distance (De) on a wheel and axle is the diamter of the wheel Resistance Distance Dr on a wheel and axle is the diameter of the axle In a screwdriver, the diameter of the handle is De and the diameter of the blade is the Dr RESISTANCEFORCE Created by C. Douglas 04-05

  41. Which screwdriver has the greatest mechanical advantage? Created by C. Douglas 04-05

  42. Which screwdriver has the greatest mechanical advantage? Created by C. Douglas 04-05

  43. TYPICAL WHEEL AND AXLE PROBLEM • The diameter of a steering wheel on a car is 40 cm and the hub of the wheel has a diameter of 10 cm • What are the De and Dr of this machine? • What is the mechanical advantage? • If the driver turns the wheel with a force of 250 N what force will the hub turn with? Created by C. Douglas 04-05

  44. effort resistance The force required to turn the wheel is the effort force Diameter of the wheel is the De The diameter of the hub of the wheel is Dr The force which the hub turns with (to turn the wheels of the car) is the Resistance force or force out Created by C. Douglas 04-05

  45. SCREW Created by C. Douglas 04-05

  46. A SCREW IS AN INCLINED PLANE THAT WRAPS AROUND A CENTRAL SOLID CORE Created by C. Douglas 04-05

More Related