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3 years ago

Pls help. I will give brainliest(:

Physics

2 answers:

algol [13]3 years ago

4 0

D I believe because it’s not a nor B and I don’t believe it’s C

kramer3 years ago

4 0

The best answer choice is C. because a rarefaction is the reduction of an items density, and is the opposite of a compression

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The revolution of the earth around the sun demonstrate what motion?

olga2289 [7]

Answer:

Anticlockwise directions

Please mark me Brainliest to help me

3 0

2 years ago

The interior space of large box is kept at 30 C. The walls of the box are 3 m high and have a ‘sandwich’ construction consisting

White raven [17]

Answer:

$\frac{\dot Q}{A} =20.129\ W.m^{-2}$

$T_1=27.58\ ^{\circ}C$ & $T_2=2.41875\ ^{\circ}C$

Explanation:

Given:

interior temperature of box, $T_i=30^{\circ}C$

height of the walls of box, $h=3\ m$

thickness of each layer of bi-layered plywood, $x_p=1.25\ cm=0.0125\ m$

thermal conductivity of plywood, $k_p=0.104\ W.m^{-1}.K^{-1}$

thickness of sandwiched Styrofoam, $x_s=5\ cm=0.05\ m$

thermal conductivity of Styrofoam, $k_s=0.04\ W.m^{-1}.K^{-1}$

exterior temperature, $T_o=0^{\circ}C$

From the Fourier's law of conduction:

$\dot Q=\frac{dT}{(\frac{x}{kA}) }$

$\dot Q=\frac{dT}{R_{th} }$ ....................................(1)

Now calculating the equivalent thermal resistance for conductivity using electrical analogy:

$R_{th}=R_p+R_s+R_p$

$R_{th}=\frac{x_p}{k_p.A}+\frac{x_s}{k_s.A}+\frac{x_p}{k_p.A}$

$R_{th}=\frac{1}{A} (\frac{x_p}{k_p}+\frac{x_s}{k_s}+\frac{x_p}{k_p})$

$R_{th}=\frac{1}{A} (\frac{0.0125}{0.104}+\frac{0.05}{0.04}+\frac{0.0125}{0.104})$

$R_{th}=\frac{1.4904}{A}$ .....................(2)

Putting the value from (2) into (1):

$\dot Q=\frac{30-0}{\frac{1.4904}{A} }$

$\dot Q=\frac{30\ A}{1.4904}$

$\frac{\dot Q}{A} =20.129\ W.m^{-2}$ is the heat per unit area of the wall.

The heat flux remains constant because the area is constant.

For plywood-Styrofoam interface from inside:

$\frac{\dot Q}{A} =k_p.\frac{T_i-T_1}{x_p}$

$20.129=0.104\times \frac{30-T_1}{0.0125}$

$T_1=27.58\ ^{\circ}C$

&For Styrofoam-plywood interface from inside:

$\frac{\dot Q}{A} =k_s.\frac{T_1-T_2}{x_s}$

$20.129=0.04\times \frac{27.58-T_2}{0.05}$

$T_2=2.41875\ ^{\circ}C$

4 0

3 years ago

Using clay electric rates, how much does it cost to watch Netflix for 4 hours on a smart tv?

OverLord2011 [107]

Answer: TVs cost between $0.0015 and $0.0176

Explanation:

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3 years ago

How does Piggy feel about being called "Piggy"?

denpristay [2]

Answer:

good because piggy loves peppa pig :3

Explanation:

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3 years ago

What is the instantaneous speed at 5 seconds? (remember s=d/t)

TEA [102]

5 seconds is a poor time to ask about, because the speed abruptly changes at exactly 5 seconds.

Up until that time, the speed has been 1 m/s. And then, at exactly 5 seconds, it becomes zero.
_________

It's also a poor question because speed is calculated from the distance covered, but the graph shows displacement, not distance. You can't really tell the distance covered from a displacement graph. For example, if an object happens to be moving in a circle around the place where it started, then the total distance covered keeps increasing, but its displacement is constant.

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4 years ago

Read 2 more answers