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UNIT 14 – SIMPLE MACHINES

UNIT 14 – SIMPLE MACHINES. Simple machine a device that is generally made of one moving part helps in making work easier Simple machines make work easier by: Multiplying force Multiplying speed Changing the direction . LEVER. a bar that is free to turn about a fixed point

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UNIT 14 – SIMPLE MACHINES

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  1. UNIT 14 – SIMPLE MACHINES

  2. Simple machine • a device that is generally made of one moving part • helps in making work easier • Simple machines make work easier by: • Multiplying force • Multiplying speed • Changing the direction

  3. LEVER • a bar that is free to turn about a fixed point • 3 parts of a lever: 1. fulcrum – pivot point or point at which the lever is resting 2. load – or resistance that needs to be carried or overcome 3. effort – or force needed to lift/carry or overcome the load

  4. Parts of a lever

  5. Effort needed to lift or move a load can be reduced by: • moving the fulcrum closer to the load • applying the effort further from the fulcrum

  6. 3 TYPES OF LEVERS: • First Class Lever = LOAD – FULCRUM – EFFORT • Second Class Lever = FULCRUM – LOAD – EFFORT -function of first class and second class levers is to multiply the effort applied in order to produce greater force • Third Class Lever = FULCRUM – EFFORT – LOAD - function of the third class levers is to multiply the speed of the effort applied so that work is done faster

  7. FIRST CLASS SECOND CLASS THIRD CLASS 3 Types of Levers

  8. FIRST CLASS LEVERS

  9. SECOND CLASS LEVERS

  10. THIRD CLASS LEVERS

  11. PULLEY – helps us to lift an object 3 Types of Pulleys: 1.FIXED PULLEY – a pulley fixed to a support - effort moves downwards while load moves upwards - function = to change direction of the effort applied - does not reduce the effort needed to lift the load; effort and load move the same distance

  12. FIXED PULLEYS

  13. Types of Pulleys • MOVABLE PULLEY - a pulley that is not fixed to a support - the pulley moves together with the load - effort and load move in the same direction - function is to reduce the effort applied - effort moves a greater distance than the load

  14. MOVABLE PULLEYS

  15. Types of pulleys • PULLEY SYSTEM – made up of more than one pulley to lift a load - made up of fixed pulleys and movable pulleys - function is to multiply the effort applied to produce a greater force to lift the load - commonly used on ships; usually called a block and tackle

  16. PULLEY SYSTEMS

  17. WHEEL AND AXLE • Made up of a wheel fixed to a rod called the axle. • The wheel is bigger than the axle. • When the wheel turns, the axle turns too. • The wheel moves a greater distance than the axle. • Function is to multiply the effort applied to produce greater force. • The wheel multiplies the effort applied to move a load at the axle

  18. WHEEL AND AXLE

  19. INCLINED PLANE • A flat surface whose endpoints are at different heights • Easier to pull or push a load up an inclined plane • Function is to reduce the effort applied • The effort moves the objects over a greater distance

  20. INCLINED PLANES

  21. GEARS • Wheels with teeth on them • Function is to change the direction of the effort • Multiply the speed of the effort • When gears interlock, they turn together

  22. GEARS

  23. PRECAUTIONARY MEASURES IN USING SIMPLE MACHINES • Use the right type of simple machines for the right job to prevent injury caused by bending or breaking levers. • Secure pulleys properly before using them and ensure that pulleys can withstand the load being lifted. • Simple machines that are sharp should be handled with care. Always cover the sharp edges when storing or transporting them.

  24. COMPLEX MACHINES • COMPLEX MACHINES – consists of several simple machines put together in order to work or operate • Parts of an airplane: - wheels - engines - wings - tail

  25. COMPLEX MACHINES

  26. http://www.sciencebuddies.org/science-fair-projects/project_ideas/Phys_img081.jpghttp://www.sciencebuddies.org/science-fair-projects/project_ideas/Phys_img081.jpg • http://www.school-for-champions.com/science/images/machines_levers-pliers.gif • http://facstaff.gpc.edu/~pgore/PhysicalScience/images/bottle-opener.jpg • http://www.diracdelta.co.uk/science/source/l/e/lever/wheelbarrow001.jpg • http://juniorengineering.usu.edu/workshops/machines/images/lever6.jpg • http://www.climatechangematters.net.au/LOTS/Phy/sub/levers/images/thumb_Lever1.gif • http://www.gmasononline.com/LEVER3.gif • http://www.legoeducation.us/sharedimages/content/ExtraLarge/XL_DOORKNOB.jpg

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