• Pixel-art sticker of Pulleya, personifying Mechanical Advantage, with the caption “More Rope, Less Pull.”

IndexForces & FieldsSticker

Pulleya

Mechanical Advantage Physics

\[F = \frac{W}{n}\]
$4.99 USD
$4.99 USD
Sale Sold out

Meet Pulleya, for whom it is more rope, less pull: sharing a load across several rope segments cuts the pull you need, but you must pull more rope. With four supporting segments in an ideal, frictionless pulley, you pull a quarter of the weight over four times the distance. Pixel-art kiss-cut sticker in 2, 3, 4 and 6 inches; equation, symbols and sources in the physics panel below.

Size
Surface

Flat $6 shipping worldwideMade to order, ships in 2–5 business days

Details

Size3″ × 3″

3″ × 3″ kiss-cut sticker.

Shipping

Flat $6 shipping on every order, worldwide, whatever's in it.

Delivery times & where we ship

Returns & replacements21 days

Every item is printed to order, so we can’t accept returns or exchanges for change of mind, or if you ordered the wrong size or colour.

Print defect, misprint, damage or the wrong item? We’ll send a free replacement, or a refund if you prefer. Report it within 21 days of delivery with a photo; no need to send it back.

Full refund & replacement policy

The physics

Meet Pulleya, a block and tackle who lets you lift a heavy load with a light pull.

In a pulley system, one continuous rope loops around several pulleys, and the load hangs from several rope segments at once. With an ideal rope and pulleys, the tension is the same all along the rope, so each supporting segment carries the same share. With n segments holding the load of weight W, the pull needed is only W/n.

With four supporting segments, as drawn in the sticker, you pull a quarter of the weight. Lifting a 400 newton load needs only 100 newtons. But energy is conserved: to raise the load 1 metre, you must pull 4 metres of rope. The work, force times distance, is the same either way.

Cranes, sailing rigs, elevators and gym machines all use multiple pulleys.

Real pulleys have friction, and the rope and lower pulleys have weight, so the actual pull needed is a bit more than W/n.

Equations

\[F = \frac{W}{n}\]
SymbolMeaningUnit
\(F\) pull needed (ideal, no friction) \(\mathrm{N}\)
\(W\) weight of the load \(\mathrm{N}\)
\(n\) number of rope segments supporting the load —

Sources

  1. Wikipedia — Block and tackle
  2. Wikipedia — Mechanical advantage

Field notes

View all
  • Pixel-art illustration for this Pixelated Physics post: three abstract pixel mascots of electromagnetism: a coil-and-magnet character, a glowing wave-equation spirit, and a spinning AC motor character, joined by arcs of field lines

    Faraday, Maxwell and Tesla: Who Did What in Ele...

    Electromagnetism was not one inventor’s story. Faraday made induction a laboratory fact, Maxwell turned fields into equations that predicted light, and Tesla patented a practical AC motor. Here is who...

    Faraday, Maxwell and Tesla: Who Did What in Ele...

    Electromagnetism was not one inventor’s story. Faraday made induction a laboratory fact, Maxwell turned fields into equations that predicted light, and Tesla patented a practical AC motor. Here is who...

  • Pixel-art illustration for this Pixelated Physics post: a pixel black hole character glowing faintly at its edge, emitting a gentle drizzle of tiny particles, a chalkboard-free starry background

    Stephen Hawking: What Did He Predict, and What ...

    Hawking’s 1974 prediction that black holes radiate is central theoretical physics — and still unobserved in astrophysical black holes. Analogue experiments are not detections. The information paradox is open. Penrose’s...

    Stephen Hawking: What Did He Predict, and What ...

    Hawking’s 1974 prediction that black holes radiate is central theoretical physics — and still unobserved in astrophysical black holes. Analogue experiments are not detections. The information paradox is open. Penrose’s...

  • Pixel-art illustration for this Pixelated Physics post: two pixel crowds: fermion characters each standing alone in their own boxes, and boson characters happily piling together into one box

    What Is the Spin–Statistics Theorem?

    The spin–statistics theorem ties a particle’s spin to the symmetry of its quantum state. Integer spin → bosons (symmetric); half-integer spin → fermions (antisymmetric). Fierz (1939) and Pauli (1940) made...

    What Is the Spin–Statistics Theorem?

    The spin–statistics theorem ties a particle’s spin to the symmetry of its quantum state. Integer spin → bosons (symmetric); half-integer spin → fermions (antisymmetric). Fierz (1939) and Pauli (1940) made...

1 3
View all