An engineer is given the job of designing the water system for a tall building. He decides to locate the pumps at ground level and feed the entire building from there. If the top floor of the building is 236 m above ground level, what must the pressure be at pump level?
you must use density*gravitational acceleration*height. density=1000kg/m^3 Gravity=9.8m/s^2 height=given=236 m 1000kg/m^3*9.8m/s^2*236m=2312800kg/(m*... = 2312800 Pa=2312.8Mpa hope this helps, looking at the units it all works out: N/m^2=kg*m/(s^2*m^2)=kg/(m*s^2)=Pa
Adding to Colin's answer, in addition to pgh, you also must add the atmospheric pressure, which is the pressure caused by the air at roughly the Earth's surface, unless whatever vessel the engineering is trying to pump the water into is a vacuum or otherwise not exposed to the air outside. atmospheric pressure: 1 atm = 1.013 x 10^5 Pa
