4–72 A person puts a few apples into the freezer at 215°C to cool them quickly for guests who are about to arrive. Initially, the apples are at a uniform temperature of 20°C, and the heat transfer coefficient on the surfaces is 8 W/m2·K. Treating the apples as 9-cm-diameter spheres and taking their properties to be r 5 840 kg/m3, cp 5 3.81 kJ/kg·K, k 5 0.418 W/m·K, and a 5 1.3 3 1027 m2/s, determine the center and surface temperatures of the apples in 1 h. Also, determine the amount of heat transfer from each apple. Solve this problem using analytical one-term approximation method (not the Heisler charts).
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Physics, 22.06.2019 13:30, kuddlebugsmommy
The two stars in a certain binary star system move in circular orbits. the first star, alpha, has an orbital speed of 36 km/s. the second star, beta, has an orbital speed of 12 km/s. the orbital period is 137 d. a) what is the mass of the star alpha? b) what is the mass of the star beta?
Answers: 1
Physics, 22.06.2019 17:40, RayshawnBoulware
A15.75-g piece of iron absorbs 1086.75 joules of heat energy, and its temperature changes from 25°c to 175°c. what is the specific heat capacity of iron?
Answers: 1
Physics, 22.06.2019 18:30, raywalker3410
Adisk with a radius of r is oriented with its normal unit vector at an angle q with respect to a uniform electric field. which of the following would result in an increase in the electric flux through the disk? check all that apply? a. increasing the area of the disk b. decreasing the given orientation angle of the disk c. decreasing the strength of the electric field d. increasing the given orientation angle of the disk, but not exceeding an angle of 90
Answers: 1
4–72 A person puts a few apples into the freezer at 215°C to cool them quickly for guests who are ab...
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