Engineering, 25.03.2020 05:04 dozsyerra

The explosion of a hydrogen bomb can be approximated by a fireball with a temperature of 7200 K, according to a report published in 1950 by the Atomic Energy Commission. (a) Calculate the total rate of radiant-energy emission for a 1.5 km diameter fireball that radiates as a blackbody. (b) Calculate the irradiation, G, on the wall of a house 40 km from the center of the blast. The blast occurs at an altitude of 16 km. (c) If the wall of the house is coated in red primer, estimate the total amount of radiation absorbed if the blast lasts 10 seconds. (d) If the wall is made of oak with a flammability limit of 650 K and a thickness of 1 cm, determine whether the wood catches on fire.

Answers: 3

Show answers

Answers

Answer from: khynia11

The rate of radiation of the energy is E_r = 1.523747635*10^9 W/m^2

The irradiation is $G =46.177\ kW/m^2$

The amount of energy absorbed is E_B = 461.772 KJ

The oak Tree would catch fire because the temperature of the blast(7200 K) is higher than the flammability limit (650 K) of the oak tree and secondly the thickness is very small

Explanation:

From the question we are told that

The temperature is T = 7200K

The diameter of the ball is d = 1.5 km = 1.5 *1000 = 1500m

Hence the radius = $= \frac{1500}{2} = 750m$

The total energy radiated can be mathematically represented as

$E = \sigma A T^4$

Where $\sigma$ is the Stefan-Boltzmann constant $\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = 5.67*10^{-8} W \ \cdot m^{-2} K^{-4}$

A is the area of a sphere = $\pi d^2 = 3.142 * 1500^2 = 7.069500 *10 ^6\ m^2$

Substituting values we have

$E = 5,67*10^{-8} * 7.069500*10^6 * 7200^4$

$=1.077*10^{15} W$

Now the state of the energy is mathematically represented as

$Rate \ of \ energy \ radiation (E_r)= \frac{E}{A} = \sigma T^4$

$= 5.67*10^{-8} * 7200^2$

= 1.523747635*10^9 W/m^2

A sketch illustrating the b part of the question is shown on the first uploaded image

looking at the height at which the blast occurs(16km) as compared to the height of the wall we notice that the height of the wall is negligibly small

from the diagram x can be calculated as follows

$x = \sqrt{40^2 + 16^2}$

= 43.0813 Km

This value of x represents the radius of the blast(assuming it is spherical ) when it is at that wall

Now the irradiation G is mathematically represented as

$G = \frac{E}{4 \pi r^2}$

Here r = 43.0813 Km = 43.0813 × 1000 = 43081.3 m

$G= \frac{1.077*10^15}{4 \pi (431081.3^2)}$

$G =46.177\ kW/m^2$

Generally the amount of energy absorbed can be mathematically represented as

$Amount \ of \ energy \ absorbed \ (E_B ) = G * t$

Where t is the time taken

Therefore E_B = 46.177 *10 = 461.77 KJ

The explosion of a hydrogen bomb can be approximated by a fireball with a temperature of 7200 K, acc

Answer from: Quest

answer:

d. attempt to find the owner, then leave your information if you cannot find them.

explanation:

d. represents both (b) and (c).

more logical as well.

b and c are to complicated.

glad i could , give me a follow, so if you need with any other question, im here.

Answer from: Quest

answer:

me yeah

explanation:

Another question on Engineering

Engineering, 04.07.2019 18:10

Acompressor receives the shaft work to decrease the pressure of the fluid. a)- true b)- false

Answers: 3

Answer

Engineering, 04.07.2019 18:10

Ajournal bearing has a journal diameter of 3.250 in with a unilateral tolerance of 20.003 in. the bushing bore has a diameter of 3.256 in and a unilateral tolerance of 0.004 in. the bushing is 2.8 in long and supports a 700-lbf load. the journal speed is 900 rev/min. find the minimum oil film thickness and the maximum film pressure for both sae 20 and sae 20w-30 lubricants, for the tightest assembly if the operating film temperature is 160°f. a computer code is appropriate for solving this problem.

Answers: 3

Answer

Engineering, 04.07.2019 19:10

What is the main objective of using reheat rankine cycle?

Answers: 3

Answer

Engineering, 04.07.2019 19:10

Acircular aluminum shaft mounted in a journal is shown. the symmetric clearance gap between the shaft and journal is filled with sae 10w-30 oil at t 30°c. the shaft is caused to turn by the attached mass and cord. develop and solve a differential equation for the angular speed of the shaft as a function of time.

Answers: 2

Answer

You know the right answer?

The explosion of a hydrogen bomb can be approximated by a fireball with a temperature of 7200 K, acc...

Questions