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:
la escuela,en casa y listo...............
Answer:
// Program is written in C++
// Comments are used to explain some lines
// Only the required function is written. The main method is excluded.
#include<bits/stdc++.h>
#include<iostream>
using namespace std;
int divSum(int num)
{
// The next line declares the final result of summation of divisors. The variable declared is also
//initialised to 0
int result = 0;
// find all numbers which divide 'num'
for (int i=2; i<=(num/2); i++)
{
// if 'i' is divisor of 'num'
if (num%i==0)
{
if (i==(num/i))
result += i; //add divisor to result
else
result += (i + num/i); //add divisor to result
}
}
cout<<result+1;
}
Answer:
True
Explanation:
Tensile testing which is also referred to as tension testing is a process which materials are subjected to so as to know how well it can be stretched before it reaches breaking point. Hence, the statement in the question is true
