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:
englishhhh pleasee
Explanation:
we dont understand sorry....
Answer:
t = 25.10 sec
Explanation:
we know that Avrami equation

here Y is percentage of completion of reaction = 50%
t is duration of reaction = 146 sec
so,


taking natural log on both side
ln(0.5) = -k(306.6)

for 86 % completion




t = 25.10 sec
Answer:
a) 280MPa
b) -100MPa
c) -0.35
d) 380 MPa
Explanation:
GIVEN DATA:
mean stress 
stress amplitude 
a) 
--------------1

-----------2
solving 1 and 2 equation we get

b) 
c)
stress ratio

d)magnitude of stress range

= 280 -(-100) = 380 MPa
Answer:
1964
Explanation:
It was discovered in 1964 when a pair of Geiger counters were carried on board a sub-orbital rocket launched from New Mexico.