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Comment on I see your canal, and raise you a water bridge

Here’s a fun fact action lab pointed out: setting aside wind, etc, the load the bridge has to be designed for is only the water that fills it.

That bridge will have the same force on it from a tanker or a kyaker.

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clockworkrat@slrpnk.net ⁨1⁩ ⁨day⁩ ago
Because boats and ships displace the heavier water?

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- derpgon@programming.dev ⁨1⁩ ⁨day⁩ ago
  Boat displacement is the amount of water the boat displaces while floating. It is equal to boat weight.
  
  So, if you put a 100 ton boat in enclosed bowl, you will of course get 100 tons more on a scale. However, if you do the same with a large surface body of water (river, lake, ocean), the water will be displaced equally over a large surface area, thus distributing the weight. You still get 100 tons more, but less over the are “under” the boat.
  
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  - batmaniam@lemmy.world ⁨1⁩ ⁨day⁩ ago
    I’m only going to be a pedant because that’s sort of the point of these conversations, that’s not a bad interpretation and I appreciate you posting it.
    
    BUT, it’s not so much that it’s “distributed” as that, so long as the boat floats, there will be a mass of water displaced exactly equal to the mass of the boat. In this case it’s displaced off the bridge (off either end). There is zero force being applied up or downstream (except during the initial transition). That’s the fun thing about incomprehensible fluids, every infinitely small point at the bottom of a water colum ONLY has the force of the column above it acting on it. A pressure gage will read the same for a square mm or square m.
    
    Spot on with the bowl though. The displaced water can’t leave the system in that case so the masses add.
    
    Heres the action lab video BTW! m.youtube.com/watch?v=SUq_tM3yGTM&pp=ygUKQWN0aW9u…
    
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    Passerby6497@lemmy.world ⁨1⁩ ⁨day⁩ ago
    
    That’s the fun thing about incomprehensible fluids
    
    MFer talking about lovecraftian non-euclidian water
    
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    JPAKx4@piefed.blahaj.zone ⁨1⁩ ⁨day⁩ ago
    I assume you mean incompressible? I can comprehend water just fine
    
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    derpgon@programming.dev ⁨1⁩ ⁨day⁩ ago
    I am no physicist, so thanks or added context!
    
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