why the work done by fluid in prove of bernoulli principle is negative?

Asked by  | 13th Dec, 2012, 06:57: AM

Expert Answer:

In the proof of Bth, in the left side work is done on the liquid,so taken positive.
in the right as the water is coming out, work is done by the system , so taken negative.
 
There is no contradiction at all....here also you can take any one positive and the other one with  the same logic will be negative. so the net result will not change...will be the same in either of the cases. that you can interpret with the same logic you applied...so can explain easily.
In ideal gas in thermodynamics, as the gas expands, dV is increasing, so we say that the work is being done by the gas and hence positive.
and vice versa.

Answered by  | 13th Dec, 2012, 10:00: AM

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