[DebNJim B]

Actually, that calculation is incorrect. You don't multiply to get 5000 #'s pressure. You should divide and get less total pressure.
Think of a snowshoe. A man weighs say 160 lbs. and his shoe has a sole of say 24 sq-in. He steps out in a foot of snow and sinks to the ground. Now he puts on snowshoes and has a sole of around 240 sq-in and now only sinks in about and inch. His total weight is spread out over a larger area. If we got 5000# of pressure at the top of a tank, they would all be exploding whether they were one piece or two.