This program extends the earlier "online shopping cart" program. (consider first saving your earlier program). (1) extend the itemtopurchase class to contain a new attribute. (2 pts) item_description (string) - set to "none" in default constructor implement the following method for the itemtopurchase class. print_item_description() - prints item_description attribute for an itemtopurchase object. has an itemtopurchase parameter.

Along steel shaft of 10 cm diameter is austenised at 870°c and then quenched in a liquid at 30oc. the average surface heat transfer coefficient is 2000 w/m2. °c. the relevant thermophysical properties of the shaft are: p=7800 kg/m", k=20 w/mk, cp=0.46 kj/kg.k calculate: a)-the time required for the center temperature to drop to 200°c. b)-the temperature at half-radius at that moment. c)-the amount of heat that had been transferred to the liquid by that time per meter length of the shaft