In a heat treatment process, a 30 mm diameter stainless steel (aisi 304) ball (ρ= 7900 kg/m3 , cp = 477 j/kg·k, k = 14.9 w/m·k) is removed from the oven at a uniform temperature of 500ºc. the ball is then subjected to a flow of air at 27ºc which provides a convection coefficient of 500 w/m2 ·k. determine: a. how long does it take for the ball to reach a minimum temperature (t) of 300ºc and the rate of heat removal (q) by each ball during this process.