Answer quickly for thumbs up

(answer is t=17min)

An small length of steel bar 1/8 inch 1/2 inch 6 inches, initially at temperature of 200C, is dropped into a sink containing melting ice. The ice is constantly being replenished so the temperature of the water in the sink does not rise above the melting point of the ice. The rate at which heat is transferred from the bar to the water, Q can be given by the expression Q(Jmin1)=UA(TbTw) where U=0.050Jmin1cm2C1, is a heat transfer coefficient A(cm2), is the exposed surface area of the bar Tb,Tw are, respectively, the surface temperature of the bar and the temperature of the water Write an energy balance on the bar (i.e. relate Tb to time, t ) and integrate it to determine the time requirod for the bar to cool down to 30C, assuming that the heat conduction in the steel bar is efticient euongha for the temperature to be considered uniform throughout the bar. The density of steel is 7.86gcm3, and the heat capacity of the steel bar is 0.460Jg1C1. 1 inch =2.54cm