Given v1 = 45 sin(ωt + 28°) V and v2 = 50 cos(ωt – 30°) V. Determine the phase angle between the two sinusoids. Please report your answer so the magnitude is positive and all angles are in the range of negative 180 degrees to positive 180 degrees. The phase angle between v1 and v2 is:

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]