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Thermodynamics (enthalpy) need help


mechanical_ph

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you can go to this pic(link): http://imageshack.us/photo/my-images/854/scan0002fh.jpg/

In Green Circle: why is K = V^2/2k? and what is the small k? is it kinetic energy?

In Red Circle: what is 778? how 778 appear in this problem?

in Black circle: why is Work=pv?

thx in advanced
just explain even if it just one question you can answer
Godbless

post-90972-0-99740900-1366291483_thumb.jpg

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Surely these terms are defined prior to the question ?

 

In any case, all you need to do is check your units. For instance, p and v are in imperial units for pressure and specific volume respectively, so check the imperial units for work, and see what happens when you multiply p and v.

 

As for the 728 and small k. Given that the equation for specific kinetic energy is [math]K=\frac{u^2}{2}[/math] where u is *velocity, this points to either a proportionality constant or a conversion factor, so work through your units.

 

Hint: look up conversion factors for 1 Btu/lbm

 

I'll leave it to you to suss out k.

 

*In your question velocity is given as v1 measured in fps (feet per second).

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