Question

A bourdon pressure gage attached to the outside of a tank containingair reads 77.0psi when the local atmospheric pressure is 760 mmHg. What will be the gage reading if the atmospheric pressure increases to 773 mmHg?

Answer 1

The gage reading when the atmospheric pressure increases to 773 mmHg is 77.3 psi

Step-by-step explanation:

`P_(abs) = P_(gauge)+P_(atm)`

where;

`P_(abs)` is absolute pressure in Psi

`P_(gauge)` is the gauge pressure in Psi

`P_(atm)` is the atmospheric pressure in Psi

Given;

Absolute pressure = 77 psi

Atmospheric pressure = 760 mmHg = 1 atm = 14.7 psi

From the equation above, Gauge pressure is:

`P_(gauge) = P_(abs)-P_(atm)` = 77 - 14.7 = 62.3 psi

Gauge pressure is 62.3 psi

⇒When the Atmospheric pressure increases to 773 mmHg:

773 mmHg = 1.0171053 atm = 14.947 psi

`P_(gauge)` = 62.3 psi,
`P_(atm)` = 14.947 psi

`P_(abs) = P_(gauge)+P_(atm)`

= 62.3 + 14.947

= 77.247 psi

≅ 77.3 psi

Therefore, the gage reading when the atmospheric pressure increases to 773 mmHg is 77.3 psi