A fan draws air from the atmosphere through a 0.30-m- dimeter round duct that has a smoothly rounded entrance. A differntial manometer connected to an opening in the wall of the duct shows a vacuum pressure of 2.5 cm of water. The densidy of air is 1.22 kg/m. Determine the volume rate of air flow in the duct in cubic fet per second. What is the horspower output of the fan