Thermodynamics (enthalpy) need help

[mechanical_ph]

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

[Royston]

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).

[mechanical_ph]

i still didnt get the part which 778 appear

i know that ft-lb/BTU must appear in this conversion coz it is in imperial units

but why 778?

can anyone answer me briefly

thx in advance

[mechanical_ph]

anyone?

[krash661]

it appears it pertains to small k,(2k)

 

re read what Royston told you.

 

this may help in a small way,

 

http://en.wikipedia.org/wiki/Template:Thermodynamic_symbols

Edited April 23, 2013 by krash661