ps14a36 - Ph 111.01 December 8, 2008 PS 14a (36) Problem 1...

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Ph 111.01 December 8, 2008 PS 14a (36) Problem 1 = Walker P. 17-13. The air inside a hot air balloon has an average temperature of 87.5 °C. The outside air has a temperature of 15.7 °C. What is the ratio of the density of air in the balloon to the density of air in the surrounding atmosphere? inside / outside = T air T balloon Solution. The density is proportional to the number of moles divided by the volume. We will use the ideal-gas equation of state, PV nRT = . Then, since the pressure is about the same inside and outside of the balloon, balloon air balloon air Pn n TT RV V ⎛⎞ == ⎜⎟ ⎝⎠ This gives the ratio that we want, () balloon air balloon air 15.7 273 0.801 87.5 273 n K T V n TK V + = + Problem 2 = Walker P. 17-14. A cylindrical flask is fitted with an airtight piston that is free to slide up and down, as shown in the figure below. Contained within the flask is an ideal gas at a constant temperature of 313 K. Initially the pressure applied by the piston and the mass is 117 kPa, and the height of the piston above the base of the flask is 23.4 cm. When additional mass is added to the
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This note was uploaded on 05/13/2010 for the course PHYSICS 111 taught by Professor Staff during the Fall '08 term at S.F. State.

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ps14a36 - Ph 111.01 December 8, 2008 PS 14a (36) Problem 1...

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