i'm stuck on a problem. Lets say you have a large water tower. and the pressure is basically static pressure from the weight of the water. But when the water starts moving through pipes is the pressure then dynamic pressure? In which would you have to calculate the pressure from 1/2 density of water times velocity ^2. And another thing, I was studying hydraulic multiplication briefly. What I studied was you have a 2 inch diameter piston moving nine inches downward with a hundred pounds force. And it pushes a 6 inch diameter piston upward 1 inch with 900 pounds force. My question is if you pushed down the large piston with a hundred pounds force, then what kind of force will the small piston get.