1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution I know that the water loses gravitational p.e. as it flows down, and since it flows through the pipe at a constant rate, v does not change, so k.e. remains the same. It left me stranded with B or D. The answer is B. What does elastic potential energy got to do with this situation? Does it got to do with increase in pressure? If so, how does pressure relate to elastic p.e.?