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Solar radiation from the sun (T=5500K) heats an asphalt driveway on a summer day. The driveway has dimensions of 4.0 x 15 m. If the asphalt driveway behaves like a black body with emissivity of 1,
a)determine the amount of heat that the driveway absorbs in 1 hour.?
b) If the surface temperature of the driveway in part (a) reaches a temperature of 38C, determine how much heat it will emit in 1 hour. Is your answer the same or different as in part a)?
Calculate the decrease in available energy when 25 kg of water at 95oC mix with 35 kg of water at 35oC, the pressure being taken as constant and the temperature of the surroundings being 15oC. (Cp of water = 4.2 kJ/kg K).b.Find entropy, enthalpy and specific volume of steam at 173oC.
mercury manometer is connected to open tank of fuel (Fig 8). Calculate a change of manometer readings
h if a level of fuel increases by ΔH. Take ΔH=0.2m, ρf=832 kg/m3, ρm=13600 kg/m3.
Suppose an empty balloon weighs 50 g and that it has a diameter of 1.5 m when it is helium filled. The density of air is 1.3 kg/m3, and the density of helium is 0.18 kg/m3. Calculate the maximum lifting force that the balloons can exert.
In an attempt to determine the specific heating capacity of copper, the following experiments were used. A copper cylinder weighing 145 g is placed in a large tub of water with a temperature of 94.0 oC. When the cylinder has been in this warm water for along time, it is lifted up and put in a thermos with 335 g of water with a temperature of 12.0 oC. This water is then heated up to 15.4 oC. What value of copper's specific heat capacity does this experiment provide? The specific heat capacity for water is 4.18·103
In a compressor of a simple gas refrigerator,air enters at -10°c and 100kpa.For a compressor pressor ratio of 10 and a turbine inlet temperature of 30°c, calculate the minimum cycle temperature and coefficient of performance.
