Does Bouyant Force Affect Scale Readings?

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    Bouyancy F=ma
AI Thread Summary
The discussion centers on whether the scale reading increases after submerging a 25N block in water. Initially, the scale reads 100N, and upon immersion, the block exerts a buoyant force of 8N upward, with a tension of 17N on the scale. The key point is that the block displaces 8N of water, effectively adding to the total weight measured by the scale. Therefore, the new scale reading will be greater than 100N due to the additional weight of the displaced water. This confirms that buoyant force does affect scale readings in this scenario.
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Homework Statement



Before you submerge a block (25N) in water, you place the container of water on a scale. The scale reads 100N.

You then immerse the block in the water, the block is also hung on a scale that reads 17N. Is the scale reading greater than, less than, or equal to 100N? ( Assume that the object does not touch the sides or bottom of the container at all.)

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Homework Equations



F=ma


The Attempt at a Solution



I believe the scale will read more even though if you do a Free Body Diagram of the Block its:

Bouyant Force + Tension of Scale - Weight = 0
Bouyant force = Weight - Tension
Bouyant force = 25N - 17N = 8N UpWard

So the Weight of the block is canceled out by the Bouyant Force + Tension. However if you think of it intuitively, if the tension of the block is not fully supporting the block itself the bouyant force will take into account weighing down the scale at the bottom therefore it will be Greater than the 100N originally. But maybe I am wrong can someone help me out this is very tricky =) Thanks again
 
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You seem to have it.

The block displaces water. 8N worth of water. It's as though there is an additional 8N worth of water in the box isn't it? So ...
 
so i am right!? awesome it does weigh more because the water displaced is 8N worth also right?
 
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