Chapter 4, Problem 22P

A 6-mm-thick stainless steel strip $\text{(k = 21 W/m}\text{.K, }p=8000{\text{ kg/m}}^{\text{3}}\text{, }and{\text{ c}}_{\text{p}}\text{= }570\text{ J/kg}\text{.K)}$ and exiting an oven at a temperature of 500°C is allowed to cool within a buffer zone distance of 5 m. To prevent thermal bums to workers who are handling the strip at the end of the buffer zone, the surface temperature of the strip should be cooled to 45°C. If the air temperature in the butler zone is 15°C and the convection heat transfer coefficient is 120 W/m² K, determine the maximum speed of the stainless steel strip.