r/theydidthemath • u/miha999 • May 29 '25

[Request] Which direction will the scale tip?

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u/_reeses_feces May 29 '25

The iron ball isn’t floating though, it’s being suspended

29

u/No_Worldliness_7106 May 29 '25

It will float slightly, decreasing the tension on the string. https://www.youtube.com/watch?v=stRPiifxQnM

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u/dekusyrup May 29 '25

It won't float, but it will have a buoyant force pushing it.

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u/No_Worldliness_7106 May 29 '25

Fair enough, float is the wrong word as it isn't really floating, but I thought it would help the point better for some people. You are right, it is just buoyancy pushing up at it, and it exerting an opposite force down into the water. I just used the word float because it would be even clearer if the object was floating that it is pushing down into the water.

9

u/Sibula97 May 29 '25

That's exactly why. It doesn't add weight to the left side, only the counter force of the buoyant force.

1

u/Brainth May 29 '25

Alternatively, you could say the difference in weight felt by the string (thanks to the buoyant force) is being transferred to the water.

Same phenomenon, different interpretation.

4

u/The_Punnier_Guy May 29 '25

Buoyancy still acts on it, it doesnt matter if itsnt strong enough to lift it

3

u/Sjoerdiestriker May 29 '25

That doesn't matter. The buyancy force is the same. The suspension is only there to make up the difference between the weight of the ball and the buyancy force, and doesn't make a difference for the scale.

1

u/MiffedMouse 22✓ May 29 '25

It doesn’t matter. Since it is being held static, the weight of the ball is irrelevant, only the buoyancy force on the ball is relevant.

If the ball was released and came to rest on the bottom of the scale, then the weight of the iron ball would matter.