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A cylinder of cross-sectional Area A is closed by a massless piston. The cylinder contains n mol of ideal gas with specific heat ratio and is initially in equilibrium with the surrounding air at temperature T and pressure P. The piston is initially at height h1 above the bottom of the cylinder. Sand is gradually sprinkled onto the piston until it has moved downward to a final height h2. Find the total mass of the sand if the process is isothermal
W=PV
W=mgh
##\Delta U=\Delta Q-W\\\\##But the system is isothermal therefore##\Delta U= 0\\\\\Delta Q =W##The Work is being done by gravity ##mg\Delta h=PV\\\\mg(h_2-h_1)=PA(h_2)\\\\m=\frac{PA(h_2)}{(h_2-h_1)g}##Answer in text is##M=\frac{PA}{g}(\frac{h_1}{h_2}-1)##
Homework Equations
W=PV
W=mgh
The Attempt at a Solution
##\Delta U=\Delta Q-W\\\\##But the system is isothermal therefore##\Delta U= 0\\\\\Delta Q =W##The Work is being done by gravity ##mg\Delta h=PV\\\\mg(h_2-h_1)=PA(h_2)\\\\m=\frac{PA(h_2)}{(h_2-h_1)g}##Answer in text is##M=\frac{PA}{g}(\frac{h_1}{h_2}-1)##