Engine oil (cp = 2100 j/kg·k) is to be heated from 20°c to 60°c at a rate of 0.3 kg/s in a 2-cm-diameter thin-walled copper tube by condensing steam outside at a temperature of 130°c (hfg = 2174 kj/kg). for an overall heat transfer coefficient of 650 w/m2 ·k, determine the rate of heat transfer and the length of the tube required to achieve it.