What is the gravitational potential energy of a 10 kg mass which is 3.4 metres above the ground? note : if using acceleration due to gravity, only use positive 9.81 m/s/s , express your answer as a number rounded to 2 decimal places.

Athin walled concentric tube exchanger is used to cool engine oil from 160°c to 60°c with water that is available at 25°c acting as a coolant. the oil and water flow rates are each at 2 kg/s, and the diameter of the inner tube is 0.5 m and the corresponding value of the overall heat transfer coefficient is 250 w/m2. oc. how long must the heat exchanger be to accomplish the desired cooling? cpwater=4.187 kj/kg-candcpengine el=2.035 kj/kg·°c, oil . 120]