Answer: the thermal conductivity of the sample is 22.4 W/m . °C
Explanation:
We already know that the thermal conductivity of a material is to be determined by ensuring one-dimensional heat conduction, and by measuring temperatures when steady operating conditions are reached.
ASSUMPTIONS
1. Steady operating conditions exist since the temperature readings do not change with time.
2. Heat losses through lateral surfaces are well insulated, and thus the entire heat generated by the heater is conducted through the samples.
3. The apparatus possess thermal symmetry
ANALYSIS
The electrical power consumed by resistance heater and converted to heat is:
Wₐ = V<em>I</em> = ( 110 V ) ( 0.4 A ) = 44 W
Q = 1/2Wₐ = 1/2 ( 44 A )
Now since only half of the heat generated flows through each samples because of symmetry. Reading the same temperature difference across the same distance in each sample also confirms that the apparatus possess thermal symmetry. The heat transfer area is the area normal to the direction of heat transfer. which is the cross- sectional area of the cylinder in this case; so
A = 1/4πD² = 1/3 × π × ( 0.05 m )² = 0.001963 m²
Now Note that, the temperature drops by 15 degree Celsius within 3 cm in the direction of heat flow, the thermal conductivity of the sample will be
Q = kA ( ΔT/L ) → k = QL / AΔT
k = ( 22 W × 0.03 m ) / (0.001963 m² × 15°C )
k = 22.4 W/m . °C
Answer:
(B) heated air in an uninsulated, unvented attic.
Explanation:
-Ice dams are formed by an interaction between snow cover, outside temperatures, and heat lost through the roof – more specifically, from heat loss through the poorly insulated ceiling of the house into the attic area and under the roof.
-Hot, humid air trapped in attics can also cause moisture to accumulate, resulting in mold or mildew.
Explanation:
The Release Train Engineer (RTE) has the main work of supporting as well as coaching the Agile Release Train (ART). They are capable of steering ART successfully and to navigate the complexity in delivering the software in large and inter-functional environments.
They serve the scrum master and coach teams to improve on the results.
The two actions or behaviors of the RTE are :
1. They try to create an environment of the mutual influence.
2. Listens and also supports the teams in problem identification as well as decision-making.
The friction force f = 10000 N
The heat transfer Q = 1.7936 KJ
<u>Explanation:</u>
Given data:
Surface area of Piston = 1 
Volume of saturated water vapor = 100 K Pa
Steam volume = 0.05 
Using the table of steam at 100 K pa
Steam density = 0.590 Kg/
Specific heat 
= 2.0267 KJ/Kg K
Mass of vapor = S × V
m = 0.590 × 0.05
m = 0.0295 Kg
Solution:
a) The friction force is calculated
Friction force = In the given situation, the force need to stuck the piston.
= pressure inside the cylinder × piston area
= 100 × 
× 0.1
f = 10000 N
b) To calculate heat transfer.
Heat transfer = Heat needs drop temperatures 30°C.
Q = 0.0295 × 2.0267 × × 30
Q = 1.7936 KJ
