Hi all! How do we define the power of a pump? I read a formula from a book which defines the power of the pump as follows: Power of the pump = Maximum back pressure * maximum flow rate / 2 Can anyone explain why the right hand side equals the left hand side? I don't understand why the LHS is divided by a factor of 2. And, is the power of a pump always the same value, no matter at any flow rate/back pressure? It seems to be that at maximum back pressure, the flow rate is zero and the pump power is zero then? Please help.