Simple machines levers
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Simple machines include the inclined plane, lever, pulley, wheel and axle, and gears. A lever is a straight or bent bar that turns around a fixed point called the fulcrum. There are three classes of levers - class 1 levers multiply force but reduce speed, class 2 levers always multiply force, and class 3 levers always increase speed but reduce force. Examples of all three classes of levers can be found in the human body.
Simple machines levers
- 4. LEVERS Lever straight/bent bar, turns about the fulcrum Fulcrum (F) axis about which the lever turns, fixed point Effort arm Load arm Principle of a lever Moment of load about F = Moment of effort about F Law of lever: M.A. = Effort arm (derivation) Load arm
- 6. CLASS I LEVER (fulcrum) Force multipliers - M.A. > 1, V.R. > 1 (greater effort arm)
- 7. CLASS I LEVER (fulcrum) M.A. = 1, V.R. = 1 (effort arm = load arm)
- 8. CLASS I LEVER (fulcrum) Gain in speed - M.A. < 1, V.R. < 1 (shorter effort arm)
- 9. CLASS I LEVER (fulcrum) Examples in the human body
- 10. CLASS II LEVER (load) Always force multipliers - M.A. > 1, V.R. > 1 (larger effort arm always)
- 11. CLASS II LEVER (load) Examples in the human body
- 12. CLASS III LEVER (effort) Produce gain in speed always - M.A. < 1, V.R. <1 (shorter effort arm always)
- 13. CLASS III LEVER (effort) Examples in the human body