KNOWLEDGE FOCUS Topic


Mechanical systems


and control Grade 7 (Terms 1, 3, 4) Simple mechanisms; first-, second- and


third-class levers. • Mechanical advantage/disadvantage: using levers (elementary qualitative treatment)


• Levers and linkages • Pneumatics and hydraulics: used to increase human strength


More simple mechanisms : wheel and axle, cranks and pulleys, gears


More simple mechanisms: wedge, gear


ratios, cams. • Mechanical systems that change the magnitude of forces involved: gear ratios


• Mechanical systems that change the rotary to linear motion: crank, cam


Task: hydraulic powered rescue equipment


Task: mine shaft headgear Grade 8 (Term 3)


Simple mechanisms as components of more complex machines designed to provide users with a mechanical


advantage: • Linked lever systems • Gears: spur, bevel, rack and pinion, worm (Link to Term 1)


• Gears: driver, idler, driven; velocity ratio/force multiplication


• Belt drive and chain drive systems: chain block, bicycle or motorcycle gear cogs


• Hydraulic/pneumatic systems • Mechanical advantage – including simple calculations


• Systems diagrams Grade 9 (Term 2) Interacting mechanical systems and sub-


systems: • Hydraulic principles: incompressibility of liquids, pressure in liquids, force transfer


• Hydraulic/pneumatic systems that use restrictors, one-way valves: hydraulic press/jack


• Gear systems: spur, bevel, rack and pinion, worm


• Mechanical control mechanisms: ratchet and pawl; cleats; bicycle brakes; disc brakes


• Belt-drive systems: with more than one stage


• Pulley systems: fixed pulley, movable pulley and multiple pulleys (block and tackle)


• Systems where mechanical, electrical or pneumatic systems are combined


Task: identify and solve problems that can be solved by mechanical systems integrated with electrical/ electronic or hydraulic or pneumatic


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