Complete and Clear Question:
A person puts a few apples into the freezer at -15°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 
840 kg/m3, 
3.81 kJ/kg·K, k = 0.418 W/m·K, and 
, 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).
Answer:
Temperature at the center of the apple, T(t) = 11.215°C
Temperature at the surface of the apple, T(r,t) = 2.68°C
Amount of heat transfer from each apple, Q = 21.47 kJ
Explanation:
For clarity and easiness of expression, the calculations are handwritten and attached as a file. Check the attached files for the complete calculation.
Answer
The same number of particles in a gas spread further apart than in the liquid or solid states.
Explanation:
The same number of particles in a gas spread further apart than in the liquid or solid states. The same mass takes up a bigger volume. This means the gas is less dense. Density also depends on the material.
Here in this question as we can see there is no air friction so we can use the principle of energy conservation
now here we know that
now plug in all values in above equation
divide whole equation by mass "m"
so height of the ball from ground will be 1.35 m
Answer:An incandescent light bulb gives only energy of the system in the form of heat. ... The roof of a house is stable but it receives energy from the surroundings and transfers energy through it towards lower temperature side which includes no mass transfer. So, it is best considered as closed system.
Explanation:
