$.$ A batch of $2-$cm$-$thick stainless steel plates $($k$=21$W$/$m$$K$,$$=8000$ kg$/$m$3,$ and Cp $=570$ J$/$kg$$K$)$ are conveyed through a furnace to be heat treated. The plates enter the furnace at $18$ C$,$ and they travel a distance of $3$ m inside the furnace. The air temperature in the furnace is maintained at $950$ C with a convection heat transfer coefficient of $150$ W$/$m$2.$K$.$ How the velocity of the plates affects the temperature of the plates at the end of the heat treatment? velocity of the plates vary from $5$ to $60$ mm$/$s