Engineering · Physics
Simple Machines
Levers, gears and pulleys you can crank — feel mechanical advantage.
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The course
7 worlds · 39 lessons
World 1 · Levers
FREEFulcrums, arms & the first machine ever used- 01What Is a Lever?A stiff bar that pivots on a point · 5 min
- 02The FulcrumWhere you place the pivot changes everything · 5 min
- 03First-Class LeversFulcrum in the middle — the crowbar · 6 min
- 04Second-Class LeversLoad in the middle — the wheelbarrow · 6 min
- 05Third-Class LeversEffort in the middle — trading force for speed · 6 min
- 06Balancing ActTorque and the law of the lever · 7 min
- 07Job Order: The Loading DockSpec a lever yourself and prove it lifts the crate · 8 min
World 2 · Gears & Pulleys
PROTooth ratios, torque and lifting with rope- 01Meet the GearToothed wheels that pass on turning force · 6 minPRO
- 02Gear RatiosCounting teeth to find the advantage · 6 minPRO
- 03Gear TrainsStacking ratios multiplies the advantage · 7 minPRO
- 04Fixed PulleysChange direction, not force · 5 minPRO
- 05Movable PulleysTwo ropes share the load · 6 minPRO
- 06Block and TackleMore pulleys, more supporting ropes · 7 minPRO
- 07Gears Meet PulleysYour first two-stage machine · 7 minPRO
- 08Job Order: The Warehouse HoistChoose gears or pulleys — not every choice works · 9 minPRO
World 3 · Ramps, Screws & Wedges
PROTrading distance for force with a slope- 01The RampAn inclined plane makes lifting a slide · 6 minPRO
- 02Steeper or Longer?Ramp angle sets the trade-off · 6 minPRO
- 03Trading Distance for ForceThe universal machine bargain · 6 minPRO
- 04The ScrewA ramp wrapped around a cylinder · 7 minPRO
- 05The WedgeA moving inclined plane · 6 minPRO
- 06Job Order: The Loading RampRamp, screw or wedge — spec it and prove it · 8 minPRO
World 4 · Compound Machines
PROChain simple machines to lift anything- 01Chaining MachinesAdvantages multiply, stage by stage · 7 minPRO
- 02Lever + PulleyA pumped handle on a hoist · 7 minPRO
- 03Gears up a RampRolling a heavy load with geared torque · 7 minPRO
- 04The WinchWheel-and-axle for winding rope · 6 minPRO
- 05Lever + GearReach plus ratio · 7 minPRO
- 06The Grand MachineGear, lever and pulley together · 9 minPRO
- 07Job Order: The Heavy LiftThe biggest crate yet — pick your machine carefully · 10 minPRO
World 5 · Advanced Compound Machines
PRONew pairs, same rule: mechanical advantage multiplies
World 6 · Statics & structures: trusses and beams
PROMember forces, stability, bridge designs and bending
World 7 · Finite element analysis: mesh, load, stress map
PROMeshes, convergence, hot spots, holes and safety factorsRead first
All guides →Guides for Simple Machines
Exam prepForces & MotionAP Physics 1 Forces and Motion: A Free Study GuideMap the forces and motion topics of an introductory physics course to free interactive lessons, with a four-week study plan and tips for the practice exams.
ParentsSun, Earth & MoonScience at Home With the Family Plan: A Weekly RoutineHow a family can use the Family plan: kid profiles, a weekly rhythm, safe kitchen-table follow-ups and good questions to ask, from a short weekly parent e-mail.
ExplainerSimple MachinesHow Levers Work: Fulcrum, Torque and Mechanical AdvantageUnderstand the three classes of lever, why a longer arm gives more lifting force, and the balance rule that ties it together. With a live simple-machines lab.