A collar A of mass m is moving with a speed v when it strikes an identical collar B that is at rest. Knowing that the coefficient of restitution between the collars is e, identify the correct relation for the energy lost in the impact as a function of m, e, and v.

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]

Modern high speed trains do not have perpendicular expansion gaps where rails are joined end-to-end any more they are mostly welded together but what might happen if there was a spell of particularly hot weather that causes inspection of the tracks?

Apressure vessel with an r/t 20 cannot be treated as thin walled vessel. a)-trune b)- false