Question

Atmospheric pressure is measured to be 14.769 psia. a. What would be the equivalent reading of a water barometer (inches of H20)? b. What would be the equivalent reading of a Mercury barometer (mm of Hg)?

Answer 1

(a) water height =408.66 in.

(b) mercury height=30.04 in.

Step-by-step explanation:

Given: P=14.769 psi ( 1 psi= 6894.76
`(N)/(m^2)` )

we know that
`P=\rho* g*h`

where
`\rho =Density,g=9.81(m)/(s^2)`

h=height.

Given that P=14.769 psi ⇒P= 101828.6 7
`(N)/(m^2)`

(a)
`P=\rho_(w)* g* h_(w)`

`\rho_(w)=1000(Kg)/(m^3)`

⇒101828.67=
`1000* 9.81* h_(w)`

`h_(w)`=10.38 m

So water barometer will read 408.66 in. (1 m=39.37 in)

(b)
`P=\rho_(hg)* g* h_(hg)`

`\rho_(hg)`=13600

So 101828.67=
`13600* 9.81* h_(hg)`

`h_(hg)`=0.763 m

So mercury barometer will read 30.04 in.