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.
Explanation:
Action and reaction are two forces that are equal in magnitude but the direction is opposite.
When a dog walks along the ground, the action force is the force that dog applies on the ground. On the other hand, the reaction force is the force that the ground applies on the dog. It is based on Newton's third law of motion.
Answer:
d. 87,500 J
e. 49,600 J
Explanation:
The total energy is the heat absorbed by the copper plus the heat absorbed by the water.
d)
E = m₁C₁ΔT + m₂C₂ΔT
E = (1 kg) (390 J/kg/°C) (10 °C) + (2 kg) (4180 J/kg/°C) (10 °C)
E = 87,500 J
e)
E = m₁C₁ΔT + m₂C₂ΔT
E = (2 kg) (390 J/kg/°C) (10 °C) + (1 kg) (4180 J/kg/°C) (10 °C)
E = 49,600 J
The speed does the block move after it is hit by the bullet that remains stuck inside the block will be 23.7 m/sec and it takes 12.07 seconds to stop.
<h3>What is the law of conservation of momentum?</h3>
According to the law of conservation of momentum, the momentum of the body before the collision is always equal to the momentum of the body after the collision.
Apply the law of conservation of momentum principle;
m₁v₁+m₂v₂cosΘ =(m₁+m₂)V
3 kg × 12 m/s + 0,1 kg × 400 m/s cos 20° = (3+0.1)V
36 + 40 cos 20° = 3.1 V
V=23.7 m/sec
The time it takes to stop when the friction coefficient between the block and the surface is 0.2 is found as;
V = u +at
V = 0+ μgt
23..7=0.2× 9.81 ×t
t=12.07 sec
Hence, it takes 12.07 seconds to stop.
To learn more about the law of conservation of momentum refer;
brainly.com/question/1113396
#SPJ1
