Aboat has an initial speed of 17 ft/s . it then increases its speed along a circular path of radius rho = 80 ft at the rate of v˙=(1.4s)ft/s2, where s is in feet. determine the time needed for the boat to travel s=70 ft .

Steel balls 12 mm in diameter are annealed by heating to 1150 k and then slowly cooled to 400 k in an air att 325 k and h -20 w/m2 k. assume the properties of the steel to be k- 40 w/m k,p 7800 kg/m3, and cp 600 j/kg k. a. determine whether lumped system method can be used to analyze this problem and if so why" b. determine the time required for the cooling process. c. determine the total amount of heat lost from each ball to the ambient air