Water is flowing through a 20 cm diameter pipe that consists of a 7 m long vertical with a 90 elbow and forces the water to be discharged through double pipe with a 15 cm diameter. Water discharged at point 3 at a velocity of 9 m/s and pressure 500 kPa. Determine the reaction force acting on the water by the elbow. The weight and friction effects are negligible. Assume the inconsiderable elevation change between point 2 and 3. 7 m y