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Stels [109]
3 years ago
6

The concrete slab of a basement is 11 m long, 8 m wide, and 0.20 m thick. During the winter, temperatures are nominally 17 C and

10 C at the top and bottom surfaces, respectively. If the concrete has a thermal conductivity of 1.4 W/m K, what is the rate of heat loss through the slab
Physics
1 answer:
Lunna [17]3 years ago
3 0

Answer:

Q = - 4312 W = - 4.312 KW

Explanation:

The rate of heat of the concrete slab can be calculated through Fourier's Law of heat conduction. The formula of the Fourier's Law of heat conduction is as follows:

Q = - kA dt/dx

Integrating from one side of the slab to other along the thickness dimension, we get:

Q = - kA(T₂ - T₁)/L

Q = kA(T₁ - T₂)/t

where,

Q = Rate of Heat Loss = ?

k = thermal conductivity = 1.4 W/m.k

A = Surface Area = (11 m)(8 m) = 88 m²

T₁ = Temperature of Bottom Surface = 10°C

T₂ = Temperature of Top Surface = 17° C

t = Thickness of Slab = 0.2 m

Therefore,

Q = (1.4 W/m.k)(88 m²)(10°C - 17°C)/0.2 m

<u>Q = - 4312 W = - 4.312 KW</u>

<u>Here, negative sign shows the loss of heat.</u>

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How much heat is needed to raise the temperature of 2 kg of copper from 20º to 30ºC. The specific heat of copper is 390 J/kgºC.
ryzh [129]

Answer:

7800 J

Explanation:

Heat needed = mass of copper x specific heat of copper x change in temperature  

Change in temperature = 30ºC - 20ºC = 10ºC

Specific heat of copper = 390 J/kgºC

Mass of copper = 2 Kg

Substituting the given values in above equation, we get –  

Heat needed = 2 Kg x 390 J/kgºC x 10ºC

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3 0
3 years ago
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sattari [20]

Answer:

The correct answers are the proportionality of the fields concerning distance, vector fields, and forces at a distance.

Explanation:

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Have a nice day!

3 0
3 years ago
Which of the following statements about planetary satellites is true? all planetary satellites are as large as our moon or bigge
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6 0
3 years ago
Read 2 more answers
What force does the water exert (in addition to that due to atmospheric pressure) on a submarine window of radius 44.0 cm at a d
Butoxors [25]
Calculate the pressure due to sea water as density*depth.
That is, 
pressure = (1025 kg/m^3)*((9400 m)*(9.8 m/s^2) = 94423000 Pa = 94423 kPa

Atmospheric pressure is  101.3 kPa
Total pressure is  94423 + 101.3 = 94524 kPa (approx)

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The force on the window is
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A van de Graaff generator accelerates electrons so that they have energies equivalent to that attained by falling through a pote
Marat540 [252]

Answer:

Hello your question is incomplete hence I will give you a general answer on how A van de Graaff generator works

answer :

If the electrons falls through a PD of 150mV the electron will gain energy of   150MeV

Explanation:

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hence if the electrons falls through a PD of 150mV the electron will gain energy of   150MeV

4 0
3 years ago
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