Question

Use these rules to work out the following problem: A U-shaped tube is connected to a box at one end and open to the air at the other end. The box is full of gas at pressure p_gas, and the tube is filled with mercury of density 1.36×104 kg/m^3. When the liquid in the tube reaches static equilibrium, the mercury column is h_1 =11.0 cm high in the left arm and h_2 = 5.50 cm high in the right arm, as shown in the figure. What is the gas pressure p_gas inside the box? Find the pressures p_A andp_B at surfaces A and B in the tube, respectively. Use p_atmos to denote atmospheric pressure.
Express your answers, separated by a comma, in terms of one or both of the variables p_gas and p_atmos.

Answer 1

Sample Questions for References 

===Question===

Use these rules to work out the following problem: A U-shaped tube is connected to a box at one end and open to the air at the other end. The box is full of gas at pressure pgas, and the tube is filled with mercury of density 1.36×104 kg/m3 . When the liquid in the tube reaches static equilibrium, the mercury column is h1 = 11.5 cm high in the left arm and h2 = 5.00 cm high in the right arm, as shown in the figure.(Figure 1) What is the gas pressure pgas inside the box?

A. Assume patmos=1.00atm. What is the gas pressure pgas?

===ANSWER===

Answer 2

Pb = Patm 

Pa = Pb - density*(H1-H2) 

Pgas = Pa 

... 

Pb = 1 atm = 101,325 Pa 

Pa = 101,325 - (1.36*10^4)*(0.115-0.055) = 100,509 

Pgas = 100,509 Pa