--- title: Pushes and pulls: what makes things move and stop — a lesson of Mova's school · trees and pragmatics description: «Pushes and pulls: what makes things move and stop», a lesson of the physics course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: A push or a pull is called a force, and a force is what starts things moving, stops them, speeds them up or turns them. --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/physics/4-pushes-and-pulls-move-and-stop/) [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/) / Pushes and pulls: what makes things mo… # Pushes and pulls: what makes things move and stop Lesson 4 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/4-pushes-and-pulls-move-and-stop/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/physics/4-pushes-and-pulls-move-and-stop/0/) — A push or a pull is called a force, and a force is what starts things moving, stops them, speeds them up or turns them. - [1](https://md.mova.elamur.ai/free/en/corpora/school/physics/4-pushes-and-pulls-move-and-stop/1/) — Kick a football and your foot pushes it for a split second; the harder the kick, the faster it flies. - [2](https://md.mova.elamur.ai/free/en/corpora/school/physics/4-pushes-and-pulls-move-and-stop/2/) — Nothing stops "by itself": a rolling ball slows down because the grass and the air keep pushing against it a little. - [3](https://md.mova.elamur.ai/free/en/corpora/school/physics/4-pushes-and-pulls-move-and-stop/3/) — Forces come in pairs: stand on a skateboard and throw a heavy ball forward, and the ball pushes you backwards just as hard. - [4](https://md.mova.elamur.ai/free/en/corpora/school/physics/4-pushes-and-pulls-move-and-stop/4/) — When two forces are equal and opposite, as in a tug of war where nobody wins, they cancel and nothing changes. - [5](https://md.mova.elamur.ai/free/en/corpora/school/physics/4-pushes-and-pulls-move-and-stop/5/) — A force is a push or a pull, and it is what changes how something moves. - [6](https://md.mova.elamur.ai/free/en/corpora/school/physics/4-pushes-and-pulls-move-and-stop/6/) — A harder kick gives a bigger push and a faster ball. - [7](https://md.mova.elamur.ai/free/en/corpora/school/physics/4-pushes-and-pulls-move-and-stop/7/) — A rolling ball slows down because the grass and the air push against it; in empty space, with nothing in the way, it would roll on for ever. - [8](https://md.mova.elamur.ai/free/en/corpora/school/physics/4-pushes-and-pulls-move-and-stop/8/) — A toy car rolls further on a smooth floor than on a carpet, because the carpet's fibres catch the wheels and push back much more. - [9](https://md.mova.elamur.ai/free/en/corpora/school/physics/4-pushes-and-pulls-move-and-stop/9/) — In a tug of war where nobody moves, both teams pull just as hard in opposite directions, so the forces cancel. - [11](https://md.mova.elamur.ai/free/en/corpora/school/physics/4-pushes-and-pulls-move-and-stop/11/) — Two people pushing a heavy wardrobe add their pushes together, and once it is sliding it is a bit easier to keep it going, because the floor grips it a bit less once it moves. - [12](https://md.mova.elamur.ai/free/en/corpora/school/physics/4-pushes-and-pulls-move-and-stop/12/) — The more mass something has, the harder it is to start, stop or turn, so a full trolley is harder to push and to stop than an empty one. - [13](https://md.mova.elamur.ai/free/en/corpora/school/physics/4-pushes-and-pulls-move-and-stop/13/) — Every push comes in a pair: when you push something, it pushes you back just as hard. - [14](https://md.mova.elamur.ai/free/en/corpora/school/physics/4-pushes-and-pulls-move-and-stop/14/) — When you jump off a small boat, your legs push the boat backwards, so it drifts away; step off carefully with a hand on the jetty. - [15](https://md.mova.elamur.ai/free/en/corpora/school/physics/4-pushes-and-pulls-move-and-stop/15/) — A balloon let go without its knot squeezes air out of its neck, and the air rushing out pushes the balloon the other way. - [16](https://md.mova.elamur.ai/free/en/corpora/school/physics/4-pushes-and-pulls-move-and-stop/16/) — Rockets work in the same way, pushing hot gas out of the back so that the gas pushes them forward. - ← previous: [Parachutes, skydivers and falling safely](https://md.mova.elamur.ai/free/en/corpora/school/physics/3-parachutes-and-falling-safely/) - next →: [Pushes and pulls all around us](https://md.mova.elamur.ai/free/en/corpora/school/physics/5-pushes-and-pulls-all-around-us/) - ↑ back to [Physics](https://md.mova.elamur.ai/free/en/corpora/school/physics/)