Consider the following: I have 2 PVC pipes, one is small enough to fit into the other with a little extra space. A rubber ring is placed around the smaller one to fill up the empty space, making a good seal to push air in and out of the larger one. Ignore any friction caused by the ring on the inside of the large pipe. The small pipe also has a strong stopper on the side that is plugged into the large pipe. The small pipe is pushed slightly up into the big one, and on the other end of the big one there is a stopper, preventing air from escaping. Imagine that it's perfectly attached and won't blow off with any amount of force. The small pipe is standing on the ground, slightly inside the large pipe, and some amount of weight is placed on top of the large pipe, say, 300 lbs. (I would use metrics, but there would be too much conversion for my situation) Question: Assuming I'm at sea level, and using your every day air, how is the pressure (psi) on the inside of the large pipe determined when you know how much weight is pushing it down? Thanks.