4 ms·
The foot is convenient for more than just human scale things. The speed of light is 1 ft/ns to within 2% and the speed of sound in air is 1 ft/ms to about 12%.
by beojan 4y ago
The foot is convenient for more than just human scale things. The speed of light is 1 ft/ns to within 2% and the speed of sound in air is 1 ft/ms to about 12%.
- deleted 4y ago[deleted]
- perilunar 4y agoThe speed of light is 3×10^8 m/s or 0.3 m/ns (accurate to 0.07%). The speed of sound is 343 m/s at 20°C, or 1 km in 3 seconds (accurate to 3%) Both of these are just as easy to remember. ft/ns and ft/ms seem pretty useless to me. I guess they work for room-sized things, but go outside and you're converting to miles anyway.
- benj111 4y agoI have issue with describing the speed of sound or light as human scale. The simplicity of remembering 1 foot is utterly drowned out by trying to appreciate what a nano second is. As a factoid it's easier to remember yes. But a factoid in isolation is useless. So unless you're going to do E=MC2 in imperial