You have a cup, it has a mass of 1 Kg.(adsbygoogle = window.adsbygoogle || []).push({});

In the cup is a liquid, with a mass of 1.5 Kg.

the Cup (and liquid) are on a weight scale (call it X).

We have another object, with known volume (call it V), attached to a spring-scale from upwards (call it Y).

The object was put inside the liquid (not floating), X reads 7.5*g N, Y reads 2.5*g N, what is the density of the liquid.

Now, what most people i know did is that they said :

The weight of cup and liquid = (1+1.5)*g = 2.5*g N

And since scale X reads 7.5*g N, then the real (not apparent) weight of the object must be 5*g N (and they start to solve from there).

What i have made is that i drew a free body diagram, and i reached the conclusion that the real weight of the object is 7.5*g N.

Who do u think is right ?

Thanks in advance.

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# You have a cup, it has a mass of 1 Kg.

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