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'Windmill': China tests world’s first megawatt-level airship to capture high winds
(interestingengineering.com)
this post was submitted on 25 Sep 2025
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Edit: I'm wrong, see edit below!
Huh? Kinetic energy increase is square, not cubic.
KE=1/2 m v^2
So every doubling of speed should increase the available kinetic energy by 4 times, not 8. 3 times the speed is 9 times the energy. Granted there are probably some efficiency gains in excess of this at the low end, ~~but as a rule that's just wrong.~~
Edit: Cool, I learned something new! I neglected to consider it in terms of power, just thought about kinetic energy.
So something like: KE = 1/2 m v^2
= 1/2 ( rho V) v^2
= 1/2 ( rho A d) (d/t)^2
= 1/2 rho A d^3 1/t^2
Where P = KE/t
Thus:
P = 1/2 rho A (d/t)^3
= 1/2 rho A v^3
Lots of other aspects I'm sure I have wrong, but I see how the cubic came to be.
I'm out of practice with my physics so apologies if this is a n00b question, but:
I'm unclear what (rho V) is and how you converted to that from mass (m). Further unclear what (rho A d) refers to.
Can you explain / link to an explainer on this?
Rho is density