A transformer for charging a power tool steps the line voltage down to 2.9 V. The output current of this transformer is 240 mA. If the transformer is ideal (100% efficient), what is the input current

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]

Estimate the change in specific internal energy au and specific enthalpy h from inlet to outlet for ethylene glycol (a liquid) flowing through each of the following devices: (a) a heat exchanger where the glycol temperature increases from 20 °c to 80 °c; (b) a pump operating at about 25 °c and increasing the glycol pressure from 100 kpa to 8 mpa.

Acountershaft is supported by two tapered roller bearings using indirect mounting. the radial bearing loads are 1120 lb for the left-hand bearing and 2190 lb for the right-hand bearing. the shaft rotates at 400 rpm and is to have an l10 life of 40,000 hours and an application factor of 1.4. assume ka2k 15, and find the required radial rating of each bearing