A small jet that has passenger windows which are $30$ cm by $39$ cm is flying at a speed of $155$ m$/$s$.$ The pressure inside the plane is atmospheric pressure and the density of air in the plane is $1\mathrm{.}29$ kg$/$m$3.$ Determine the following.

$($a$)$ pressure difference between the inside and outside of the window

Pa

$($b$)$ force exerted on the window by this pressure difference

N