How Fast? | Force | Physics for All | FuseSchool

Click here to see more videos: That plane is supersonic. How fast do you think that is? In this video we’ll look at the speed of some everyday items. You should already know that speed is a measure of the distance an object travels in a certain time, and that it’s calculated using this equation. Which can also be remembered using a formula triangle If you haven’t calculated speeds before, watch this video first. These two people are standing 990 metres apart. When this person speaks, there is a 3 second delay before the 2nd person hears the words. How fast is sound travelling? With a distance of 990m and time of 3 seconds The speed of sound in air is 330m/s. This is a rough approximation for the speed of sound if the air temperature is 0 degrees celsius. If the air is warmer, sound travels faster. Let’s add in km per hour to give a better context. Passenger planes fly at about 900 to 1000km/hr. Slower than the speed of sound... Is it possible to fly faster than the speed of sound? Yes, some fighter jets can. Going faster than the speed of sound is called super sonic speeds. You won’t hear the jets until they’ve already passed over your head - because the sound is actually slower and travelling behind them! On the ground, the sound waves are heard as a sonic boom. So that’s sound and passenger jets. How fast is light in comparison? Have you ever wondered why you see the flash of lightning before you hear the rumble of thunder? This is because the speed of light is much, much faster than the speed of sound. The thunder and lightning both come from the same source and occur at the same time, however light travels at just under 300 million metres per second. Whereas sounds travels at a measly 330m/s. Next time you see lightning, count how many seconds before you hear the thunder. This tells you roughly how far away the lightning is. If you’re a km person, remember 3 seconds for 1km And if you’re a miles person, remember 5 seconds for 1 mile. Now let’s slow it down a lot… how fast do we walk, run and cycle? Wow, compare that to sound, planes and light!! Again, let’s add in km/hr because often those speeds are easier to imagine. What do you think makes some days feel windier than others? It’s the speed of the wind. Air is always moving, but the faster it moves the windier it feels. A gentle breeze moves at 3.5 to 5.5 m/s. Faster than we run! On a windy day it gets up to about 14m/s. The highest wind speed ever recorded was 135m/s in a tornado in America. Although not as fast as a commercial plane, tornadoes can cause some serious destruction. They can destroy buildings, uproot trees and hurl vehicles hundreds of metres. There we have the speeds of some different every day things. Whilst we can’t go as fast as light, we sure can go faster than the speed of sound. CREDITS Animation & Design: Joshua Thomas Narration: Dale Bennet Script: Bethan Parry VISIT us at, where all of our videos are carefully organised into topics and specific orders, and to see what else we have on offer. Comment, like and share with other learners. You can both ask and answer questions, and teachers will get back to you. These videos can be used in a flipped classroom model or as a revision aid. Twitter: Access a deeper Learning Experience in the FuseSchool platform and app: Friend us: This Open Educational Resource is free of charge, under a Creative Commons License: Attribution-NonCommercial CC BY-NC ( View License Deed: ). You are allowed to download the video for nonprofit, educational use. If you would like to modify the video, please contact us:

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