Question

5-18E Hydrogen is contained in a piston-cylinder device at 14.7 psia and 15 ft'. At this state, a linear spring (F « x) with a spring constant of 15,000 lbf/ft is touching the piston but exerts no force on it. The cross-sectional area of the piston is 3 f?. Heat is transferred to the hydrogen, causing it to expand until its vol- ume doubles. Determine (a) the final pressure, (b) the total work done by the hydrogen, and (c) the fraction of this work done! against the spring. Also, show the process on a P-V diagram.

Answer 1

Patm Pnsde Prce body diagam ap Pion Pnsetb AFat Pam A Pnsido Patm A (om Pre Won Pmy de Veies n sy ith P nst4. Psia atek 0t fatm )lahn 14-7 Ps1 u. U-Vi al Compe m of spng A 230-15 5 et FSPomg 2- 15 coo a 5 5000 1b KYL (7500) 25000 1 25 000 b 141 7 3

hPaie3500047 144 168-2 PSIa (b) isk done Ge 14.9 PSia 4. P 1s8-2144 Ib 7A Aota o tape 20ida! :.wak dane AC434168-24) (30-15] w 1913a lb. (C) wok dene b agar n Spring k WawnC15000s- 187 500 lb- SPain fracton af warl aleme againtSPsng k1Soo 21१ ।32 t: 0.8556