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An average person generates heat at a rate of 84 W while resting. Assuming one-quarter of this heat is lost from the head and disregarding radiation, determine the average surface temperature of the h...
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An aluminum soda can 150 mm in length and 60 mm in diameter is placed horizontally inside a refrigerator compartment that maintains a temperature of 4°C. If the surface temperature of the can is 36°C,...
See AnswerQ: An incandescent lightbulb is an inexpensive but highly inefficient device that converts
An incandescent lightbulb is an inexpensive but highly inefficient device that converts electrical energy into light. It converts about 10 percent of the electrical energy it consumes into light while...
See AnswerQ: Thermal energy generated by the electrical resistance of a 5-mm
Thermal energy generated by the electrical resistance of a 5-mm-diameter and 4-m-long bare cable is dissipated to the surrounding air at 20°C. The voltage drop and the electric current across the cabl...
See AnswerQ: Electric power is to be generated by installing a hydraulic turbine–
Electric power is to be generated by installing a hydraulic turbine–generator at a site 120 m below the free surface of a large water reservoir that can supply water at a rate of 1500 kg/s steadily. D...
See AnswerQ: A 0.4-m-diameter spherical tank of negligible
A 0.4-m-diameter spherical tank of negligible thickness contains iced water at 0°C. Air at 25°C flows over the tank with a velocity of 3 m/s. Determine the rate of heat transfer to the tank and the ra...
See AnswerQ: A 300-W cylindrical resistance heater is 0.75 m
A 300-W cylindrical resistance heater is 0.75 m long and 0.5 cm in diameter. The resistance wire is placed horizontally in a fluid at 20°C. Determine the outer surface temperature of the resistance wi...
See AnswerQ: How is the thermal entry length defined for flow in a tube
How is the thermal entry length defined for flow in a tube? In what region is the flow in a tube fully developed?
See AnswerQ: Consider laminar forced convection in a circular tube. Will the heat
Consider laminar forced convection in a circular tube. Will the heat flux be higher near the inlet of the tube or near the exit? Why?
See AnswerQ: A 12-m-long section of a 5-cm
A 12-m-long section of a 5-cm-diameter horizontal hot-water pipe passes through a large room whose temperature is 27°C. If the temperature and the emissivity of the outer surface of the pipe are 73°C...
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