--- title: Pulleys, gears and big machines — a lesson of Mova's school · trees and pragmatics description: «Pulleys, gears and big machines», a lesson of the physics course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: At school assembly someone pulls the flagpole rope down and the flag climbs up: a single wheel at the top, a pulley, simply turns your dow --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/physics/35-pulleys-gears-and-big-machines/) [home](https://md.mova.elamur.ai/free/en/) / [corpora](https://md.mova.elamur.ai/free/en/corpora/) / [school](https://md.mova.elamur.ai/free/en/corpora/school/) / [Physics](https://md.mova.elamur.ai/free/en/corpora/school/physics/) / Pulleys, gears and big machines # Pulleys, gears and big machines Lesson 35 of the physics course of Mova's primary school: 16 sentences, each with its syntax tree and pragmatics. The lessons are written for Mova, and their agreed trees are part of Mova corpus 0.4 (CC BY-SA 4.0). How Mova does on its tests: [the lesson at school](https://md.mova.elamur.ai/free/en/school-run/physics/35-pulleys-gears-and-big-machines/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/physics/35-pulleys-gears-and-big-machines/0/) — At school assembly someone pulls the flagpole rope down and the flag climbs up: a single wheel at the top, a pulley, simply turns your downward pull into an upward lift. - [1](https://md.mova.elamur.ai/free/en/corpora/school/physics/35-pulleys-gears-and-big-machines/1/) — Thread a rope through several pulleys and the load hangs on many lengths of rope that share its weight, so a builder pulls with much less force, but must pull much more rope. - [2](https://md.mova.elamur.ai/free/en/corpora/school/physics/35-pulleys-gears-and-big-machines/2/) — Gears are toothed wheels that turn each other: a small gear driving a big one turns it slowly with a strong twist, a big one driving a small one spins it fast, and two gears side by side always turn opposite ways. - [3](https://md.mova.elamur.ai/free/en/corpora/school/physics/35-pulleys-gears-and-big-machines/3/) — Cranes and lifts use a heavy counterweight like a seesaw partner, so the motor only has to lift the difference between the load and the weight. - [4](https://md.mova.elamur.ai/free/en/corpora/school/physics/35-pulleys-gears-and-big-machines/4/) — Every one of these machines swaps force for distance or speed; none of them gives energy for free. - [5](https://md.mova.elamur.ai/free/en/corpora/school/physics/35-pulleys-gears-and-big-machines/5/) — A single pulley changes the direction of a pull, so you can pull down, using your own weight, to lift something up. - [6](https://md.mova.elamur.ai/free/en/corpora/school/physics/35-pulleys-gears-and-big-machines/6/) — With several pulleys, more lengths of rope share the load, so you pull with less force but must pull much more rope. - [7](https://md.mova.elamur.ai/free/en/corpora/school/physics/35-pulleys-gears-and-big-machines/7/) — A crane uses pulleys, a long arm and a heavy counterweight that balances the load like a seesaw, and it has a load limit for each distance along the arm so it does not tip over. - [8](https://md.mova.elamur.ai/free/en/corpora/school/physics/35-pulleys-gears-and-big-machines/8/) — The gears on a bike are toothed wheels joined by the chain: a small gear at the back makes the wheel turn faster, a big one makes pedalling easier. - [9](https://md.mova.elamur.ai/free/en/corpora/school/physics/35-pulleys-gears-and-big-machines/9/) — Gears in a clock let one motor turn the minute hand twelve times round for each single turn of the hour hand. - [10](https://md.mova.elamur.ai/free/en/corpora/school/physics/35-pulleys-gears-and-big-machines/10/) — Two meshing gears always turn in opposite directions, and a third gear in between makes the last one turn the same way as the first. - [11](https://md.mova.elamur.ai/free/en/corpora/school/physics/35-pulleys-gears-and-big-machines/11/) — A lift is pulled up by cables over a wheel, with a counterweight going down as it goes up; lifts have several cables and safety brakes, so falling is almost impossible. - [12](https://md.mova.elamur.ai/free/en/corpora/school/physics/35-pulleys-gears-and-big-machines/12/) — An escalator is a long loop of steps pulled round by a motor and gears, and the steps flatten at the ends so you can step on and off. - [13](https://md.mova.elamur.ai/free/en/corpora/school/physics/35-pulleys-gears-and-big-machines/13/) — A water wheel at an old mill is turned by flowing water, and its axle drives gears that turn heavy millstones to grind flour. - [14](https://md.mova.elamur.ai/free/en/corpora/school/physics/35-pulleys-gears-and-big-machines/14/) — A car jack uses a screw or a liquid pump so that many small easy turns of a handle add up to lifting a whole car. - [15](https://md.mova.elamur.ai/free/en/corpora/school/physics/35-pulleys-gears-and-big-machines/15/) — You must never go under a car held up only by a jack, because it can slip. - ← previous: [Wheels, axles, ramps and screws](https://md.mova.elamur.ai/free/en/corpora/school/physics/34-wheels-axles-ramps-and-screws/) - next →: [Speed: fast and slow](https://md.mova.elamur.ai/free/en/corpora/school/physics/36-speed-fast-and-slow/) - ↑ back to [Physics](https://md.mova.elamur.ai/free/en/corpora/school/physics/)