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Pachacha [2.7K]

3 years ago

15

A circular ceramic plate that can be modeled as a blackbody is being heated by an electrical heater. The plate is 30 cm in diame

ter and is situated in a surrounding ambient temperature of 15°C where the natural convection heat transfer coefficient is 12 W/m2·K. If the efficiency of the electrical heater to transfer heat to the plate is 80%, determine the electric power that the heater needs to keep the surface temperature of the plate at 220°C.

1 answer:

denis23 [38]3 years ago

5 0

Answer:

Q = 125.538 W

Explanation:

Given data:

D = 30 cm

Temperature $T_\infity = 15$ degree celcius

$T_S = 220 + 273 = 473 K$

Heat coefficient = 12 W/m^2 K

Efficiency 80% = 0.8

$Q = hA(T_S - T_{\infty}) \eta$

$= 12(\frac{\pi}{4} 0.3^2) (473 - 288) 0.8$

Q = 125.538 W

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Answer:

a. See Explanation Below

b. No

Explanation:

a.

Interpreting the statements line by line.

First, the prolog clauses need to be initialised, as follows:

:- dynamic freezing/0, precipitation/0, snowing/0, raining/0.

If it is raining or snowing, then there is precipitation.

The statement is splited in two.

1st, if it is raining then there is precipitation

Or

2nd, if it is raining, then there is precipitation.

So, both statements are given as:

precipitation :- raining.

precipitation :- snowing.

If it is freezing and there is precipitation, then it is snowing.

This is a conditional statement that checks if it is freezing AND there's is precipitation.

If true, then it is snowing.

The above statement is given as:

snowing :- freezing, precipitation.

If it is not freezing and there is precipitation, then it is raining.

This is a conditional statement that checks if it is not freezing AND there's is precipitation.

If true, then it is raining.

The not clause is represented as \+

The above statement is the given as:

raining :- \+ freezing, precipitation.

It is snowing.

This is represented as follows

snowing.

So, the full prolog clause is as follows

:- dynamic freezing/0, precipitation/0, snowing/0, raining/0.

precipitation :- raining.

precipitation :- snowing.

snowing :- freezing, precipitation.

raining :- \+ freezing, precipitation.

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b. What answer does Prolog give to the following queries:

Is it freezing

No

Reason;

All of the conditions above point to raining or snowing; none points to freezing.

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An experiment compares the initial speed of bullets fired from two handguns: a 9 mm and a 0.44 caliber. The guns are fired into

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Answer:

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v2: mass of the bob with the bullet after being hit

v2 = v1 * mb / (M + mb)

Upon being impacted the bob will acquire speed v2, this implies a kinetic energy. The bob will then move and raise a height h. Upon acheiving the maximum height it will have a speed of zero. At that point all kinetic energy will be converted into potential energy.

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Ep = (M + mb) * g * h

Ek = Ep

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1/2 * v1^2 * mb^2 / (M + mb)^2 = g * h

v1^2 = g *h * (M+ mb)^2 / (1/2 * mb^2)

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The height h that it reaches is related to the length L of the pendulum arm and the angle it forms with the vertical.

h = L * (1 - cos(a))

$v2 = \sqrt{\frac{g * L * (1 - cos(a)) * (M+ mb)^2}{\frac{1}{2} * mb^2}}$

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$v2 = \sqrt{\frac{9.81 * L * (1 - cos(4.3)) * (10+ 0.006)^2}{\frac{1}{2} * 0.006^2}} = \sqrt{L} * 391$

For the 0.44 caliber:

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Answer:

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(b)

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