[Aerkuld]

Another question that's odd is the penultimate question about the air entering the cylinder. I don't see the difference between the downward motion of the piston sucking air in and the atmospheric pressure pushing air in. For example, if the cylinder was sitting there and not moving no air would enter the cylinder. Surely the real answer is the air enters the cylinder due to the pressure differential created by the piston moving down and lowering the pressure in the cylinder below atmospheric. So isn't either answer technically correct?