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3 years ago

In places of hot climate it is advised that the outer walls of houses be painted white. Explain.

2 answers:

3 0

Darker colors absorb heat, While lighter colors don't. If a house is painted black in Arizona, The black color will absorb the heat making the temperature inside the house very hot even with the AC on. If a house in Arizona is painted White, The heat will bounce off the White color, making the temperature inside the house cooler.

Hope this helps!

ivanzaharov [21]3 years ago

3 0

Answer:

Have you ever noticed people working outside in the hot sun and how you never really see them wearing black shirts or pants. This is because dark colors absorb heat, however light colors, such as white, do the exact opposite. Instead of absorbing the heat from the light, light colors reflect it. So people usually paint there houses lighter colors in hot places to keep their there houses from absorbing heat so it does not cost them so much on electricity bills for air conditioning.

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What is the Scientific definition of friction?

seropon [69]

Friction<span> is the resistance to motion of one object moving relative to another. It is not a fundamental force, like gravity or electromagnetism. Instead, scientists believe it is the result of the electromagnetic attraction between charged particles in two touching surfaces.
Hope this is of great help to you, and happy studying~!
~Mistermistyeyed.</span>

8 0

4 years ago

Read 2 more answers

Steam is to be condensed on the shell side of a heat exchanger at 150 oF. Cooling water enters the tubes at 60 oF at a rate of 4

zalisa [80]

Answer:

a. 572Btu/s

b.0.1483Btu/s.R

Explanation:

a.Assume a steady state operation, KE and PE are both neglected and fluids properties are constant.

From table A-3E, the specific heat of water is $c_p=1.0\ Btu/lbm.F$ , and the steam properties as, A-4E:

$h_{fg}=1007.8Btu/lbm, s_{fg}=1.6529Btu/lbm.R$

Using the energy balance for the system:

$\dot E_{in}-\dot E_{out}=\bigtriangleup \dot E_{sys}=0\\\\\dot E_{in}=\dot E_{out}\\\\\dot Q_{in}+\dot m_{cw}h_1=\dot m_{cw}h_2\\\\\dot Q_{in}=\dot m_{cw}c_p(T_{out}-T_{in})\\\\\dot Q_{in}=44\times 1.0\times (73-60)=572\ Btu/s$

Hence, the rate of heat transfer in the heat exchanger is 572Btu/s

b. Heat gained by the water is equal to the heat lost by the condensing steam.

-The rate of steam condensation is expressed as:

$\dot m_{steam}=\frac{\dot Q}{h_{fg}}\\\\\dot m_{steam}=\frac{572}{1007.8}=0.5676lbm/s$

Entropy generation in the heat exchanger could be defined using the entropy balance on the system:

$\dot S_{in}-\dot S_{out}+\dot S_{gen}=\bigtriangleup \dot S_{sys}\\\\\dot m_1s_1+\dot m_3s_3-\dot m_2s_2-\dot m_4s_4+\dot S_{gen}=0\\\\\dot m_ws_1+\dot m_ss_3-\dot m_ws_2-\dot m_ss_4+\dot S_{gen}=0\\\\\dot S_{gen}=\dot m_w(s_2-s_1)+\dot m_s(s_4-s_3)\\\\\dot S_{gen}=\dot m c_p \ In(\frac{T_2}{T_1})-\dot m_ss_{fg}\\\\\\\dot S_{gen}=4.4\times 1.0\times \ In( {73+460)/(60+460)}-0.5676\times 1.6529\\\\=0.1483\ Btu/s.R$

Hence,the rate of entropy generation in the heat exchanger. is 0.1483Btu/s.R

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3 years ago

How many type of expansion physic

Yuki888 [10]

Answer:

Three types of thermal expansion are linear expansion,s superficial expansion,cubical expansion

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3 years ago

A solar eclipse will occur Group of answer choices

myrzilka [38]

Answer:

3. at new Moon only when the Moon is on the ecliptic.

Explanation:

Solar eclipse is the condition when the moon comes in between the sun and the earth. In this condition the moon casts its shadow on the earth.

Whether the eclipse is a total solar eclipse, a partial solar eclipse or an annular solar eclipse depends on various factors, but the position of the moon must be on the same orbital plane as that of the earth's orbit around the sun.

The sun is about 400 times larger than the moon in size and the sun is almost 400 times farther from the earth than the moon is, this makes it possible for the moon to cover the sun completely leading to a complete solar eclipse.

As we know that the orbit of the earth around the sun and the orbit of the moon around the earth is elliptical which leads to a variation in the distance from their rotating centers, so not of every eclipse the moon covers the sun completely developing an annular eclipse.

When the moon is close enough to the earth on the ecliptic but not completely aligned in between the sun and the earth leads to a partial solar eclipse.

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3 years ago

A _______ is a tool often used to measure the amount of force exerted by an object

Marina86 [1]

Answer:

Force meter

Explanation:

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3 years ago