$1/10$ scale model of a trailer body is tested in a pressurized wind tunnel. The frontal area of the model is $0\mathrm{.}16$ m$^2.$ At the wind speed of V$=85$ m$/$s$,$ the drag force of the model is $175$ N$.($The density of air in the wind tunnel is $3\mathrm{.}5$ kg$/$m$^3.)$ Calculate the aerodynamic drag coefficient of the model and the aerodynamic drag force on the prototype at a speed of $75$ mph$,$ if the air density is $1\mathrm{.}3$ kg$/$m$^3.$