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3 years ago

6

If you bake a cake in the oven in your kitchen, you can feel the warmth of the oven if you stand next to it. This is an example

of

1 answer:

Nitella [24]3 years ago

6 0

I believe this is an example of transferred heat. Are there any multiple choice given?

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For heat transfer purposes, an egg can be considered to be a 5.5-cm-diameter sphere having the properties of water. An egg that

Harrizon [31]

Answer:

The time taken is $t = 40007 sec$

Explanation:

From the question we are told that

The diameter of the egg is $d_e = 5.5cm = \frac{5.5}{100} = 5.5*10^{-2}m$

The initial temperature of egg the $T_e = 4.3^{o}C$

The temperature of the boiling water $T_b = 100^oC$

The heat transfer coefficient is $H = 800 W/m^2 \cdot K$

The final temperature is $T_e_f = 74^oC$

The thermal conductivity of water is $k = 0.607 W/m^oC$

The diffusivity of the egg $\alpha = 0.146 * 10^{-6} m^2 /s$

Using one term approximation

We have the

$\frac{T_e_f - T_b}{T_e - T_b} = Ae^{-\lambda ^2 \tau}$

The radius is $r = \frac{5.5*10^ {-2}}{2} =2.75*10^{-2}m$ Note that this radius is approximation to that of a real egg

Now we need to obtain the Biot number which help indicate the value of $A \ and \ \lambda$ to use in the above equation

The Biot number is mathematically represented as

$Bi = \frac{H r}{k}$

Substituting values

$Bi = \frac{800 * 2.75 *10^{-2}}{0.607}$

$= 36.24$

So for this value which greater than 0.1 the coefficient $\lambda_1 \ and \ A_1$ is

$\lambda = 3.06632$

$A = 1.9942$

Substituting this into equation 1 we have

$\frac{74- 100}{4.3 - 100} = 1.9942 e^{-(3.0632^2) \tau}$

$0.2717= 1.9942 e^{-(3.0632^2) \tau}$

$0.2717= 1.9942 e^{-9.383 \tau}$

$0.13624 = e^{-9.383 \tau}$

Taking natural log of both sides

$-1.993 = -9.383\ \tau$

$\tau = 0.2124$

The time required for the egg to be cooked is mathematically represented as

$t = \frac{\tau r^2}{\alpha }$

substituting value is

$= \frac{0.2124 * 2.75 *10^{-2}}{0.146 *10^{-6}}$

$t = 40007 sec$

8 0

3 years ago

List at least 3 ways for you to represent your data graphically

yawa3891 [41]

1. circle graph
2. Bar graph
3. line graph

hope this helps

6 0

1 year ago

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Since friction is a force,<br> what unit is friction<br> measured In???

dimaraw [331]

It would be measured in newtons :)

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3 years ago

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What is the pressure exerted when a force of 20 N is applied to an object over an area of 2 m2 ?

IgorC [24]

(20 N)/(2 m²) = (20/2) N/m² = 10 Pa

_____

The pascal (Pa) is the derived SI unit of pressure equal to 1 N/m².

8 0

3 years ago

An object has a mass of 10 kilograms and is accelerating at 5 m/s/s, what force pushed the object?

Katen [24]

Answer:

force pushed the object = 10 × 5 = 50N

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2 years ago