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Not Everything That Stops Working Has Lost Its Value Feeling broken by life's setbacks? Discover why your value never decreases because of failure, pain, or difficult seasons. Learn the powerful lesson behind the broken machine and why your worth remains unchanged. The Broken Machine That Changed Everything Imagine walking into a workshop and finding an old industrial machine covered in dust and rust. It has not worked for years. Most people pass it without a second thought. "It is finished." "It is useless." "It belongs in the scrapyard." Those are the words many would use. Then an experienced engineer enters. Instead of seeing a useless machine, he sees possibility. He opens the casing, examines the internal parts, replaces a few worn components, reconnects the wiring, and powers it on. Within moments, the machine is running again. What changed? Not its value. Only its condition. That simple scene teaches one of the most important lessons about human...

Simple Machine

Edwin Ogie Library

Simple Machines — Definition, Types, MA, VR & Efficiency

Introduction to Simple Machines

Simple machines are the most basic mechanical devices that change the direction or magnitude of a force. They form the foundation of complex machinery and make work easier by trading force for distance (or vice versa).

This lesson covers definitions, the 6 classical types, mechanical advantage (MA), velocity ratio (VR) and efficiency, with worked examples and a CBT quiz.

Types of Simple Machines

  • Lever — rigid bar rotating about a fulcrum.
  • Pulley — wheel and rope to change direction and mechanical advantage.
  • Inclined Plane — raise loads using less force over a longer distance.
  • Wedge — converts force to lateral forces to split objects.
  • Screw — inclined plane around a cylinder converting rotation to linear motion.
  • Wheel & Axle — two radii rotating together to multiply force or distance.

Mechanical Advantage (MA)

MA is the factor by which a machine multiplies an input force:

MA = Output Force / Input Force

Higher MA means less effort for the same load (ignoring losses).

Velocity Ratio (VR)

VR is the ratio of distances moved by effort and load (ideal, lossless):

VR = Distance moved by effort / Distance moved by load

In an ideal machine (no friction), MA = VR.

Efficiency

Efficiency measures how well input work is converted to useful output work:

Efficiency (%) = (MA / VR) × 100

Real machines have <100% efficiency due to friction and losses.

Summary & Applications

Simple machines trade force for distance to make work easier. Understanding MA, VR, and efficiency helps analyze or design devices ranging from hand tools to mechanical lifting systems.

10 Worked Examples (solutions hidden)

Example 1 — Lever MA

Q: Fulcrum 2 m from load and 6 m from effort. Effort = 50 N. Find output force.

Example 2 — Pulley (block & tackle)

Q: VR = 4, effort = 30 N. Ideal output force?

Example 3 — Inclined plane

Q: Ramp length 5 m, height 1 m. Effort 100 N. Find ideal output force (MA).

Example 4 — Wedge

Q: Effort 200 N produces output 600 N. Find MA.

Example 5 — Screw

Q: How does pitch affect screw MA?

Example 6 — Wheel & Axle VR

Q: Wheel radius 0.5 m, axle radius 0.1 m. Find VR.

Example 7 — Efficiency

Q: MA = 4, VR = 5. Find efficiency.

Example 8 — Compound machine

Q: Lever (MA=3) attached to pulley (MA=4). Overall MA?

Example 9 — Partial variation model

Q: How does y = kx + c model fixed losses?

Example 10 — Car jack

Q: How does a car jack apply simple machine principles?

30-Question CBT Quiz — Simple Machines

Press Start Quiz. There is a 5-second countdown, then 15 minutes to answer 30 questions. Quiz auto-submits when time ends. Attempts saved locally.

Time Remaining: 15:00

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