我仲係唔.明..THXXX

Q: 首先本來 PRESSURE=1ATM 而VOLUME=1.5, 之後VOLUME由1.5增到1.6再減少到1.5 PRESSURE唔會變返1ATM? 仍舊在(1.5/1.6)ATM

Don't forget that this is a pump, its purpose is to pump air out from the vessel.

When you pull the piston, the volume of air increases from 1.5 m^2 to 1.6 m^2.The 0.1 m^ of air would be pumped out from the vessel . Because there is now less mass of air remaining in the vessel, the pressure would decrease to lower than 1 atm. The volume of air in the vessel, which is 1.5 m^3, is always the same.


2011-08-03 22:45:06 補充：
Sorry for my typing mistake on the unit in volume. The unit of which should be m^3 instead of m^2.