Some aerodynamic exercises. I am in 3rd year of Aerospacial Engineering.
Can anyone help me? I am studying from home and I have been struggling with this. Thanks!
Son ejercicios de aerodinámica del 3 año de Ingeniería aeroespacial.
Puede alguien ayudarme? Con esta situación me cuesta estudiar y entender el temario. Gracias!

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]