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Comment by jasonlfunk | Hacker News Reader

I thought all of these were interesting except number 3. The rest were common “misunderstandings” in popular culture. #3 seems more like internal physicist pedantry.

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To be honest I found most of them to be fairly pedantic. I knew all except number 8 (Lorentz contraction is new to me), but all of them are of the style "might seem that way but technically..."

I didn't dislike the article though, that's not really what I mean to say. Was conveniently to the point and I can just lookup more about Lorentz contraction if I want to :)

#3 pops up when you start reading up on meteorology. I was quite recently surprised by this myself, when some article on climate I was reading started talking about gravity waves...

The only one I didn't like was #6 - I think it may be wrong. Not just because of language use (words gain multiple meanings over time; dieting!weight != physics!weight), but also because, while weight is indeed a force (a vector), it's also proportional to mass - so if you lose mass, you also lose weight.

Right, but when you lose weight you don't necessarily lose mass. You may have just gone to the moon (or Everest, I guess).

Or simpler boarding an airplane. If I remember correctly the effect is around 0,5% which can be measured with a normal scale.

I don't know if you can measure that, the airplane would have to be flying perfectly level (to at least within 0.5%).

0.5% is around a pound for a lot of people.. should be ok, isnt it?

It's not the magnitude of the measurement, it's that if the airplane is descending at 1 degree when you measure, you'll get around 1% less weight than your actual mass. If the airplane is descending at 90 degrees, you weigh nothing.

If the airplane descends at 90 degrees, I have a different problem :-)

Eh just wait until it gets to one meter from the ground and jump off, a one-meter jump will be no problem.

Fair enough.

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