1. The problem statement, all variables and given/known data Determine the reaction force from water flowing through a clean 0.02cm (Diamater assumed) hole in tank depth 3m 2. Relevant equations P = rho.g.h A = Pi.R^2 P=F/A 3. The attempt at a solution P = rho.g.h = 29400 Pa A = Pi.R^2 = 0.00031415 m^2 P = F/A -> F = PA = 9.236 Newtons Looks solid to me, but on the internet I found an equation for the reaction force in this case as: F(Reaction) = 10^3 (Rho water) * 2*g*h.A and the 2 is making me unsure. Am I overlooking something or is the formula I found just a dud?