--- title: Forces — pushes, pulls, friction and magnets — a lesson of Mova's school · trees and pragmatics description: «Forces — pushes, pulls, friction and magnets», a lesson of the world course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: A force is a push or a pull. --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/world/51-forces/) [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/) / [World](https://md.mova.elamur.ai/free/en/corpora/school/world/) / Forces — pushes, pulls, friction and m… # Forces — pushes, pulls, friction and magnets Lesson 51 of the world course of Mova's primary school: 19 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/world/51-forces/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/0/) — A force is a push or a pull. - [1](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/1/) — Forces can start something moving, stop it, speed it up, slow it down, turn it or change its shape. - [2](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/2/) — When you kick a ball you push it, and when you open a drawer you pull it. - [4](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/4/) — Friction is a force that appears when two surfaces rub against each other. - [5](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/5/) — It always works against the movement, so it slows things down and turns some of the motion into heat. - [6](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/6/) — Rough surfaces make more friction than smooth ones: a sledge slides far on smooth ice but stops quickly on grass or gravel. - [8](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/8/) — Magnets pull on iron and steel, and they can pull or push other magnets without touching them. - [9](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/9/) — A force is a push or a pull. - [10](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/10/) — A force can change how fast something moves, the direction it moves or its shape. - [11](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/11/) — Friction acts between surfaces that rub and works against the movement. - [12](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/12/) — Rough surfaces make more friction than smooth surfaces. - [13](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/13/) — Rubbing your hands together makes them warm because friction turns motion into heat. - [14](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/14/) — Oil and water on a surface reduce friction, which is why wet floors are slippery. - [15](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/15/) — Gravity is the pull of the Earth that makes things fall downwards. - [16](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/16/) — Air resistance is a kind of friction from the air; a parachute uses it to fall slowly. - [17](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/17/) — Every magnet has a north pole and a south pole. - [18](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/18/) — Opposite poles of two magnets attract and like poles repel. - [19](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/19/) — Magnets attract iron, steel, nickel and cobalt, but not wood, plastic, glass, gold, copper or aluminium, which drinks cans are made of. - [20](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/20/) — A magnetic force can act through air, paper and water without touching. - ← previous: [Thinking like a geographer: rivers, mountains and deserts](https://md.mova.elamur.ai/free/en/corpora/school/world/50-why-the-earth-is-so/) - next →: [Simple machines and how they help](https://md.mova.elamur.ai/free/en/corpora/school/world/52-simple-machines/) - ↑ back to [World](https://md.mova.elamur.ai/free/en/corpora/school/world/)