Question

Pressure is determined as force per unit area of the surface. The SI unit of pressure, pascal is as shown below:
1Pa = 1N $m^{-2}$
If mass of air at sea level is 1034 g $cm^{-2}$, calculate the pressure in pascal.

Answer 1

"Force" acting "per unit area" of the surface called is pressure.

Mathematically, it can be written as follows

$P\quad =\quad \frac { F }{ A }$

From the given mass of air at sea level =$1034 g{ cm }^{ -2 }$

Substitute the given value into the pressure formula

$=\quad \frac { 1034g\quad \times \quad 9.8{ ms }^{ -2 } }{ { cm }^{ 2 }\quad  } \quad \times \quad \frac { 1\ kg }{ 1000g } \quad \times \quad \frac { (100{ ) }^{ 2 } { cm }^{ 2 } }{ 1 { m }^{ 2 } }$

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

Let's convert the units into Pa.  

We know,

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

Then,

$1pa\quad =\quad 1N{ m }^{ -2 }\quad =\quad 1kg\quad { m }^{ -2 }{ s }^{ -2 }$

$1Pa\quad =\quad 1kg\quad { m }^{ -1 }{ s }^{ -2 }$

$1pressure\quad =\quad 1.01332\quad \times \quad { 10 }^{ 5 }Pa$ ."