# Pressure is determined as force per unit area of the surface.

Question.

Pressure is determined as force per unit area of the surface. The SI unit of pressure, Pascal is as shown below

$1 \mathrm{~Pa}=1 \mathrm{~N} \mathrm{~m}^{-2}$

If mass of air at sea level is $1034 \mathrm{~g} \mathrm{~cm}^{-2}$, calculate the pressure in Pascal.

Solution:

Pressure is defined as force acting per unit area of the surface.

$=1.01332 \times 10^{5} \mathrm{~kg} \mathrm{~m}^{-1} \mathrm{~s}^{-2}$

We know

$1 \mathrm{~N}=1 \mathrm{~kg} \mathrm{~ms}^{-2}$

Then

$1 \mathrm{~Pa}=1 \mathrm{Nm}^{-2}=1 \mathrm{~kg} \mathrm{~m}^{-2} \mathrm{~s}^{-2} 1$

$P a=1 \mathrm{~kg} m^{-1} s^{-2}$

$\therefore$ Pressure $=1.01332 \times 10^{5} \mathrm{~Pa}$