Explain what causes the atmospheric pressure. Derive the equation to show that the atmospheric pressure changes from Smoky Mountain to Greensboro. Then use the equation you derived to calculate the gauge pressure and the absolute pressure in the following question: A mercury manometer at 70(F) is used to measure the pressure of a sealed tank. It reads 25.62(in). The local acceleration of gravity is 32.243(ft)(s)2. The local atmospheric pressure is 1 atm. What are the gauge and absolute pressures in (psia) being measured? The density of mercury at 70(F) is 13.543 gcm3