Quote:
Originally Posted by TriX5
The bag is quite rigid and I doubt it changes shape much with a change in pressure. When you remove air from it, it rolls in on itself and thus lowers the car. In effect it works like a piston, not like an expanding balloon.
I know the gas law but that does not explain how it exerts upward force to keep the car from dropping down.
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When I say rigid, I talk in the physics sense. It is NOT a rigid body. You just said yourself, it rolls on itself...and it does so when pressure is minimized.
P=nRT/V, V is constant.
When you change the pressure inside the membrane, the membrane becomes "stiffer," because there are more gas molecules per unit volume (aka pounds per square inch aka psi).
Let me ask you a question, when you inflate your tires, do you increase the volume or the pressure of air inside?