1. The problem statement, all variables and given/known data Water is pumped through a hose-pipe at a rate of 90 kg per minute. It emerges from the hose-pipe horizontally with a speed of 20 m/s.What is the force is required from a person holding the hose-pipe to prevent it moving backwards? 2. Relevant equations F=ma--? Ft=mv-mu 3. The attempt at a solution 90kg/min=0.025kg/s This is m/t So if we assume u=0m/s Then, F= 0.025 x 20 (using Ft=mv-mu) F= 0.5N The answer is 30N Can we assume that u is 0m/s?