Answer:
a) What is the surface temperature, in °C, after 400 s?
T (0,400 sec) = 800°C
b) Yes, the surface temperature is greater than the ignition temperature of oak (400°C) after 400 s
c) What is the temperature, in °C, 1 mm from the surface after 400 s?
T (1 mm, 400 sec) = 798.35°C
Explanation:
oak initial Temperature = 25°C = 298 K
oak exposed to gas of temp = 800°C = 1073 K
h = 20 W/m².K
From the book, Oak properties are e=545kg/m³ k=0.19w/m.k Cp=2385J/kg.k
Assume: Volume = 1 m³, and from energy balance the heat transfer is an unsteady state.
From energy balance:
Initial temperature wall =
Surface temperature = T
Gas exposed temperature =
There mag be water on Mars but it’s not very easy to spot, but that is besides the point,
Mars is a smaller planet then Earth, thus it has less gravity, meaning when water evaporates into the atmosphere of the planet the water slowly escapes into space, so there is less and less water on the planet.
Hope this helps!
er:
Explanation:Technician A says that primary vibration is created by slight differences in the inertia of the pistons between top dead center and bottom dead center. Technician B says that secondary vibration is a strong low-frequency vibration caused by the movement of the piston traveling up and down the cylinder. Who is correct? O A. Neither Technician A nor B OB. Technician B O C. Both Technicians A and B D. Technician A
Answer:
Maximum number of vehicle = 308
Explanation:
See the attached file for the calculation.
The work done during the process is 359 btu
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<u>Explanation:</u>
Given-
P1 = 15psia
P2 = 140 psia
V1 = 7ft³
a = 5 psia/ft³
b = C
P = aV +b
Work done, W = ?
P1 = aV1 + b
15 = 5 (7) + b
b = -20 psia
P2 = aV2 + b
140 = 5 ( V2) - 20
V2 = 32 ft³
The work done by the process is the area under the curve which is trapezoidal.
Therefore,
Work done, W = area of trapezoid
= (P2 + P1 / 2) (V2 - V1)
= ( 140 + 15 / 2 ) ( 32 - 7)
= 1937.5 psia ft³
= 1937.5/ 5.4039 = 359 btu
Therefore, the work done during the process is 359 btu