During a picnic on a hot summer day, the only available drinks were those at the ambient temperature of 90°F. In an effort to cool a 1 2-fluid-oz drink in a can, which is 5 in high and has a diameter of 2.5 in. a person grabs the can and starts shaking it in the iced page 311 water of the chest at 32°F. The temperature of the drink can be assumed to be uniform at all times, and the heat transfer coefficient between the iced water and the aluminum can is 30 Bta1rfi2°F. Using the properties of water for the drink, estimate how long it vi11 take for the canned drink to cool to 40°F. Solve this problem using lumped system analysis. Is the lumped system analysis applicable to this problem? Why?
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Heat and Mass Transfer: Fundamentals and Applications
- At a constant pressure, how does a volume of gas vary with respect to the absolute temperature?arrow_forwardNewton's Law of Cooling - Differential Equations The rate at which a body cools is proportional to the difference in temperature between the body and its surroundings. If a body in air at 0°C will cool from 200°C to 100°C in 40 minutes, how many more minutes will it take the body to cool from 100°C to 50°C?arrow_forwardA 20-cm diameter copper ball is to be heated from 110°C to an average temperature of 170°C in 90 minutes. Taking the average density and specific heat of copper in this temperature range to be p=8950 kg/m and Cp=0.395 kJ/kg • °C, respectively, determine the total amount of heat transfer to the copper ball in kj (Area of sphere: TID2; Volume of sphere=TTD/6)? A 88.64 kJ B 886.4 kl 78.84 kJ D 788.4 kJarrow_forward
- Ice water of 0°C is stored in a spherical container made of steel with an inner diameter of 3 m and a thickness of 1 cm. This container is located in a place where the external temperature is 25℃. The temperature of the entire container is assumed to be 0°C. If thermal resistance in the container is ignored, obtain (a) the heat transfer rate to ice water, and (b) the amount of ice that melts for 24 hours. The melting heat of ice at atmospheric pressure is 333.7 kJ/kg. The emissivity of the outer wall of the container is 0.75, and the convective thermoelectric transfer coefficient is 30 W/m2·K. The average temperature of the surrounding surface for radiation is 15℃. ***I would appreciate it if sir could write it in a way that I could read it well.**arrow_forwardConsider a house that has a floor space of 15m x 12m and an average height of 2.7 m at 150m elevation where the standard atmospheric pressure is 84.1 kPa (shown in figure below). Initially the house is at a uniform temperature of 10°C. Now the electric heater is turned on, and the heater runs until the air temperature in the house rises to an average value of 21°C. Determine the amount of energy transferred to the air assuming (a) the house is air-tight and thus no air escapes during the heating process and (b) some air escapes through the cracks as the heated air in the house expands at constant pressure. Also determine the cost of this heat for each case if the cost of electricity in that area is $0.080/kWharrow_forwardHi, can you help me to answer this question using the first law of thermodynamics formula to explain this event? On a hot summer day, a student turns his fan on when he leaves his room in themorning. When he returns in the evening will the room be warmer or cooler than theneighborouing rooms ? Explain your answer using the first law of thermodynamics.Assume ALL doors and windows are kept closed.arrow_forward
- i need the answer quicklyarrow_forwardA father and son conducted the following simple experiment on a hot dog which measured 12.5 cm in length and 2.2 cm in diameter. They inserted one food thermometer into the midpoint of the hot dog and another one was placed just under the skin of the hot dog. The temperatures of the thermometers were monitored until both thermometers read 20°C, which is the ambient temperature. The hot dog was then placed in 94°C boiling water and after exactly 2 min they recorded the center temperature and the skin temperature of the hot dog to be 59°C and 88°C, respectively. Assuming the following properties for the hot dog: r = 980 kg/m3 and cp = 3900 J/kg·K and using transient temperature charts, determine (a) the thermal diffusivity of the hot dog, (b) the thermal conductivity of the hot dog, and (c) the convection heat transfer coefficient.arrow_forwardHEAT TRANSFER SUBJECTarrow_forward
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