--- title: Seat belts, crashes and keeping safe — a lesson of Mova's school · trees and pragmatics description: «Seat belts, crashes and keeping safe», a lesson of the physics course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: In a crash the car stops in a moment, but everything inside it, you, your bag and the dog, keeps moving forward at the speed the car --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/physics/37-seat-belts-crashes-and-keeping-safe/) [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/) / Seat belts, crashes and keeping safe # Seat belts, crashes and keeping safe Lesson 37 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/37-seat-belts-crashes-and-keeping-safe/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/physics/37-seat-belts-crashes-and-keeping-safe/0/) — In a crash the car stops in a moment, but everything inside it, you, your bag and the dog, keeps moving forward at the speed the car had. - [1](https://md.mova.elamur.ai/free/en/corpora/school/physics/37-seat-belts-crashes-and-keeping-safe/1/) — A seat belt stops you together with the car and spreads the force over the strong bones of your shoulder and hips, which is why it saves lives. - [2](https://md.mova.elamur.ai/free/en/corpora/school/physics/37-seat-belts-crashes-and-keeping-safe/2/) — Cars are built to soften the stop: the front crumples slowly, an airbag puffs out in a split second, and a longer, softer stop means a smaller force on the people inside. - [3](https://md.mova.elamur.ai/free/en/corpora/school/physics/37-seat-belts-crashes-and-keeping-safe/3/) — Nothing heavy can stop instantly: a car needs time and distance, and a heavy train needs over a kilometre, so the safest plan is never to be in the way. - [4](https://md.mova.elamur.ai/free/en/corpora/school/physics/37-seat-belts-crashes-and-keeping-safe/4/) — Being seen is the first safety and being protected is the second, for a cyclist in bright clothes and a helmet just as for a child near a lorry's blind spot. - [5](https://md.mova.elamur.ai/free/en/corpora/school/physics/37-seat-belts-crashes-and-keeping-safe/5/) — In a crash the car stops suddenly but the people inside keep moving forward, and a seat belt stops them together with the car. - [6](https://md.mova.elamur.ai/free/en/corpora/school/physics/37-seat-belts-crashes-and-keeping-safe/6/) — A seat belt spreads the force over strong bones, the shoulder and hips, not the soft tummy or neck. - [8](https://md.mova.elamur.ai/free/en/corpora/school/physics/37-seat-belts-crashes-and-keeping-safe/8/) — Younger children use booster seats so the adult belt crosses their shoulder and hips instead of their neck and tummy. - [9](https://md.mova.elamur.ai/free/en/corpora/school/physics/37-seat-belts-crashes-and-keeping-safe/9/) — An airbag fills with gas in a split second and slows your head more gently than the hard wheel; small children must not sit in front of an airbag. - [10](https://md.mova.elamur.ai/free/en/corpora/school/physics/37-seat-belts-crashes-and-keeping-safe/10/) — A car's front crumple zone squashes in a crash and makes the stop take a little longer, so the force on the people is smaller, while the strong cabin keeps its shape. - [11](https://md.mova.elamur.ai/free/en/corpora/school/physics/37-seat-belts-crashes-and-keeping-safe/11/) — A loose bag on a seat keeps moving in a crash and becomes a flying object; heavy things go in the boot and pets ride in a carrier or harness. - [12](https://md.mova.elamur.ai/free/en/corpora/school/physics/37-seat-belts-crashes-and-keeping-safe/12/) — A cyclist's helmet softens a knock to the head, and bright clothes and lights help drivers see the cyclist. - [13](https://md.mova.elamur.ai/free/en/corpora/school/physics/37-seat-belts-crashes-and-keeping-safe/13/) — It is a myth that a car can stop instantly: even the best brakes need time and distance. - [14](https://md.mova.elamur.ai/free/en/corpora/school/physics/37-seat-belts-crashes-and-keeping-safe/14/) — Big vehicles have blind spots; if you cannot see the driver's face in the mirror, the driver cannot see you. - [15](https://md.mova.elamur.ai/free/en/corpora/school/physics/37-seat-belts-crashes-and-keeping-safe/15/) — A fast train can need over a kilometre to stop, because it is very heavy and steel wheels on steel rails have little grip; that is why level crossings have barriers. - ← previous: [Speed: fast and slow](https://md.mova.elamur.ai/free/en/corpora/school/physics/36-speed-fast-and-slow/) - next →: [Rockets, record speeds and motion everywhere](https://md.mova.elamur.ai/free/en/corpora/school/physics/38-rockets-record-speeds-and-motion-everywhere/) - ↑ back to [Physics](https://md.mova.elamur.ai/free/en/corpora/school/physics/)