Q$2.$ A hard disk drive $($HDD$)$ generates a constant heat flux $=750$ W$/$m$2$ on its top surface, which can be approximated as a flat rectangular plate measuring $=10$ cm long by $=15$ cm wide. A cooling fan forces air flow along the length direction $(),$ which results in a freestream velocity $$ $=5$ m$/$s$.$ The freestream air temperature $$ $=17$C$.$

a$)$ Calculate the convective thermal resistance and surface temperature. $($remember: all values are reported with four significant digits$).$

b$)$ A blockage or partial fan failure causes a drop in cooling air velocity to $25\%$ of the original value. Calculate the surface temperature again under these new conditions. If the maximum allowable temperature for the drive to operate reliably is $85$C$,$ comment on the likelihood of failure.