Q3/ A U-tube mercury manometer with one arm open to atmosphere is used to measure pressure in a steam pipe. The level of mercury in open arm is 87.5 mm greater than that in the arm connected to the pipe. Some of steam in the pipe condenses in the manometer arm connected to the pipe. The height of this column is 37 mm. The atmospheric pressure is 76 cm of Hg. Find the absolute pressure of steam?

Hi, please can you answer quickly I appreciate your assistance.

Question 6 pls. Complete soln and units

Hello. Our instructor solved this question and subtracted the product of water's height and specific weight from the P1 pressure, as well as oil's. He didn't factor air pressure into the equation. What is the reason why we do not use open air pressure to solve the problem?