Added: 1 year ago
From: khanacademy
Views: 12,784
Sort by time | Sort by thread (beta)

Link to this comment:

Share to:

All Comments (11)

Sign In or Sign Up now to post a comment!
  • The ISA temp is 15C degrees or 59F at sea level not roughly 20, just FYI. Liked the vid.

  • Spectacular video; however, the question still aches: how come no equations? The subject we’re dealing with (which is to say, Mach quantities and the nature of sound) is easy enough…

  • I've downloaded the whole course, it's marvel. English was worth learning just for the sake of understanding your lectures.

    Please do oneday lecture on imaginary (or complex) numbers. They are part of schooll curriculum although do understand it's purpose and logic. The complex numbers are so artificial and yet they are tough everywhere

  • I could have sworn there was some international standard which defined Mach numbers as being the speed of sound at sea level at a given temperature and atmospheric pressure (in order to make it a reliable constant), but now I can't find a reference to that. Perhaps I'm thinking of something else and not Mach numbers?

  • @Ormaaj - You're thinking of the 'Standard atmosphere', google it.

  • @JimNtexas Ah thanks that's very interesting - though I don't think I've heard of that one.

  • Only criticism: why do you have to say miles?

  • @stainermcbain He is American, that is what they use to measure speed of a regular physical object. Other countries may use (metric units) kilometres per hour

  • @xcelpast Apart from the American mile there is also the Nautical Mile, which is actually a very reasonable and sane unit of length. One Nautical Mile corresponds to one minute of angle on the Earth surface. As you know the angle is measured in degrees (of angle). If you want to measure more precisely you can also measure in degrees, minutes (1/60'th of a degree) and seconds (1/60 of a minute). Now if you take Earth's center as your origin of measurement.......

  • .......and traverse one minute of a degree on the on the sea level you have covered exactly one mile. That is why the Nautical Mile is so useful to sailors and pilots. They use it because it corresponds to the angular coordinates they are using the Latitude and Longitude.

    By the way 1NM is agreed to stand for 1852 meters.

  • @stainermcbain

    Why not? He gives you in in meters per second, easily convertable to kilometers per hour.. so why not give in Miles per hour also?

Loading...
Alert icon
0 / 00Unsaved Playlist Return to active list
    1. Your queue is empty. Add videos to your queue using this button:
      or sign in to load a different list.
    Loading...Loading...Saving...
    • Clear all videos from this list
    • Learn more