--- title: Balance: the centre of gravity — a lesson of Mova's school · trees and pragmatics description: «Balance: the centre of gravity», a lesson of the physics course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: Every object acts as if all its weight sat at one point, its centre of gravity, and it balances when that point is right above what holds i --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/physics/8-balance-the-centre-of-gravity/) [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/) / Balance: the centre of gravity # Balance: the centre of gravity Lesson 8 of the physics course of Mova's primary school: 15 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/8-balance-the-centre-of-gravity/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/physics/8-balance-the-centre-of-gravity/0/) — Every object acts as if all its weight sat at one point, its centre of gravity, and it balances when that point is right above what holds it up. - [1](https://md.mova.elamur.ai/free/en/corpora/school/physics/8-balance-the-centre-of-gravity/1/) — Balance a ruler on one finger and it stays only when your finger is under its middle; stick clay on one end and the balancing point moves towards the clay. - [3](https://md.mova.elamur.ai/free/en/corpora/school/physics/8-balance-the-centre-of-gravity/3/) — Your body balances all the time without you noticing: when you lean forward, your bottom goes back, and your eyes and inner ears tell your brain which way you are tilting. - [4](https://md.mova.elamur.ai/free/en/corpora/school/physics/8-balance-the-centre-of-gravity/4/) — Every object acts as if all its weight sat at one point, called its centre of gravity. - [5](https://md.mova.elamur.ai/free/en/corpora/school/physics/8-balance-the-centre-of-gravity/5/) — A ruler balances on your finger when your finger is right under its middle; a lump of clay on one end moves the balancing point towards the clay. - [6](https://md.mova.elamur.ai/free/en/corpora/school/physics/8-balance-the-centre-of-gravity/6/) — Standing on one leg, you keep moving to keep your centre of gravity over your foot, and with your eyes shut it gets much harder. - [7](https://md.mova.elamur.ai/free/en/corpora/school/physics/8-balance-the-centre-of-gravity/7/) — A wobbly toy stands back up because its heavy weight sits low in its round base, and ships carry heavy weight low down for the same reason. - [8](https://md.mova.elamur.ai/free/en/corpora/school/physics/8-balance-the-centre-of-gravity/8/) — Something tips over only when its centre of gravity goes outside its base, so wide, low things are hard to tip. - [9](https://md.mova.elamur.ai/free/en/corpora/school/physics/8-balance-the-centre-of-gravity/9/) — Racing cars are built low and wide so they do not tip over in fast corners. - [10](https://md.mova.elamur.ai/free/en/corpora/school/physics/8-balance-the-centre-of-gravity/10/) — When you lean forward, your hips go back to keep your balance, so with your back against a wall you cannot touch your toes. - [11](https://md.mova.elamur.ai/free/en/corpora/school/physics/8-balance-the-centre-of-gravity/11/) — A tightrope walker's long pole is slow to turn, which gives the walker time to correct wobbles. - [12](https://md.mova.elamur.ai/free/en/corpora/school/physics/8-balance-the-centre-of-gravity/12/) — People lean away from a heavy bag to bring their centre of gravity back over their feet, and two bags, one in each hand, are easier than one twice as heavy. - [13](https://md.mova.elamur.ai/free/en/corpora/school/physics/8-balance-the-centre-of-gravity/13/) — On a seesaw, a heavy person near the middle can balance a light person far from the middle. - [14](https://md.mova.elamur.ai/free/en/corpora/school/physics/8-balance-the-centre-of-gravity/14/) — A tall thing tips over slowly, so a broom is easier to balance on your palm than a pencil. - [15](https://md.mova.elamur.ai/free/en/corpora/school/physics/8-balance-the-centre-of-gravity/15/) — Tiny tubes of liquid in your inner ear tell your brain which way you are tilting, and after spinning the liquid keeps moving, which makes you dizzy. - ← previous: [Living with friction: oil, wheels and grip](https://md.mova.elamur.ai/free/en/corpora/school/physics/7-living-with-friction/) - next →: [Riding a bike: why it stays up](https://md.mova.elamur.ai/free/en/corpora/school/physics/9-riding-a-bike/) - ↑ back to [Physics](https://md.mova.elamur.ai/free/en/corpora/school/physics/)