A section of U-shaped pipe. The inner diameter of the pipe is 0.5 m. Air enters one section of the pipe at an average speed of 100 m/s and flows out the other section at the same speed, but in the opposite direction. The flow pressure at the inlet and outlet is the ambient pressure. Calculate the magnitude and direction of the force exerted by the air flow on the pipe. Air density is 1.23 kg/m3.