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 = 
Answer and Explanation:
In any experiment, the observed values are the actual values obtained in any experiment.
The calculated values are the values that are measured by using the observed values in a formula.
The observed values are primary values whereas the calculated values are the secondary values as calaculations are made using observed values.
Yes, if the observed values are of low accuracy.
The values should be recorded with proper care and attention in order to avoid any error.
Answer:
Headlights are required to be used 1/2 hour after sunset to 1/2 hour before sunrise, when windshield wipers are being used, when visibility is less than 1000 feet, or when there is insufficient light or adverse weather.
Explanation:
hope this helps
Answer: It means "Do it yourself".
Explanation: You're welcome!
Answer:
d. All of the above would require an EIS.
Explanation:
A document prepared with the aim of describing the impacts of suggested operations on the environment is an Environmental Impact Statement (EIS). There was a mistake. An Environmental Impact Statement (EIS) is therefore a report describing the environmental effects resulting from a current action. All of the activities above would have an effect on the environment and therefore must fill an EIS
