Answer:
a. 0.6 W/mK b. 45 kJ c. 0.025 m²K/W
Explanation:
a. Determine the thermal conductivity (k) for the insulating material.
The rate at which heat is transferred across the insulating material P = kAΔT/L where K = thermal conductivity, A = area of insulating material = 25 cm × 25 cm = 0.25 m × 0.25 m = 0.0625 m², ΔT = temperature difference between inside and outside = 10.0 °C = 10.0 K and L = thickness of insulating material = 15 mm = 0.015 m
So, making k subject of the formula, we have
k = PL/AΔT
Now, P = 25.0 W = heat delivered to box = heat delivered to insulating material per second.
k = 25.0 W × 0.015 m/(0.0625 m² × 10.0 K)
k = 0.375 Wm/(0.625 m²K)
k = 0.6 W/mK
b. Find the energy transferred (Q) through the material after a half hour.
Since quantity of energy transferred Q = Pt where P = heat delivered to box = heat delivered to insulating material per second = 25.0 W and t = time the heat is delivered = 1/2 h = 0.5 h = 0.5 × 60 min = 30 min × 60 s/min = 1800 s
So, Q = 25.0 W × 1800 s
Q = 45000 J
Q = 45 kJ
c. Find the R-value of the insulation.
R - value, R = L/k = 0.015 m/0.6 W/mK = 0.025 m²K/W
Multiple Choice
What is the relationship between rules of inference and proofs?
O Each rule of inference is made up of a proof.
O Rules of inference are used to explain proofs.
O Rules of inference are used to construct proofs.
O Each rule of inference is a different type of proof.
Question #7
Answer:https://global.oup.com/us/companion.websites/9780199385423/student/ch6/mcq/ just go here
Explanation:
A book of the Law was found in the Temple, which was being repaired, during the___
year of Josiah's reign.
1.eighteenth
2.seventeenth
3.nineteenth
Answer:
2
Explanation:
Answer:
Its 1 eighteenth
Explanation:
According to an account in 2 Kings and 2 Chronicles, Hilkiah was a kohen gadol (High Priest) of the Temple of Jerusalem during the reign of King Josiah of Judah (639-609 BC) and the discoverer of "The Book of the Law" in the Temple, in the 18th year of Josiah's Reign (622 BC).
Does the size of the conductor determine the amount of current it can
carry? *
Yes
No
Yes. It does influence the amount of current it can carry, and it could also alter the resistance.
Dimension these please.
Answer:
86
Explanation:
If a black fluid is leaking from your vehicle, you most likely have a
leak.
motor oil
power steering fluid
antifreeze
transmission fluid
Answer:
Cool
Explanation:
If a black fluid is leaking from your vehicle, you most likely have a motor oil leak. Hence option a is correct.
What is vehicle?Vehicle is defined as a device, typically on wheels with an engine, that is used to move people or objects, especially on land: Last night, a truck driver lost his life when his car flipped over. Due to the growing distances between places like home, work, educational institutions, shopping malls, and recreational facilities, mobility is becoming more and more crucial.
The most frequent sort of fluid loss is engine oil. If the liquid pool is located closer to the front of your car, the engine is likely where it came from. Enter the liquid using your finger or a piece of paper towel. The fluid will be brown or black, slippery to the touch, and have a faint burnt smell if it is engine oil.
Thus, if a black fluid is leaking from your vehicle, you most likely have a motor oil leak. Hence option a is correct.
To learn more about vehicle, refer to the link below:
https://brainly.com/question/13390217
#SPJ2
Why is it important to apply and handle finishing materials only in an approved area
Answer:
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