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3 years ago

PLEASE HELP ME

Physics

1 answer:

Monica [59]3 years ago

5 0

Answer:

im pretty sure it is C. Insulation

Explanation:

because it says reduced, and basically ur insulating the fire.

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A car travelling at 20 m/s due north along the highway makes a right turn on to a side road that heads due east. It takes 50 s f

Marrrta [24]

Answer: initial velocity: 20 m/s

time taken to complete the turn: 50s

final velocity: 15 m/s

average acceleration= final velocity-initial velocity/time taken - 0s( 0 is taken here as there was no initial time)

= 15-20/50-0

= -5/50= -0.1 ms^2

3 0

2 years ago

Suppose your surface body temperature averaged 90 degrees F. How much radiant energy in W/m^2 would be emitted from your body?

Debora [2.8K]

$493 \; \text{W}\cdot \text{m}^{-2}$ .

<h3>Explanation</h3>

The Stefan-Boltzmann Law gives the energy radiation <em>per unit area</em> of a black body:

$\dfrac{P}{A} = \sigma \cdot T^{4}$

where,

$P$ the total power emitted,
$A$ the surface area of the body,
$\sigma$ the Stefan-Boltzmann Constant, and
$T$ the temperature of the body in degrees Kelvins.

$\sigma = 5.67 \times 10^{-8} \;\text{W}\cdot \text{m}^{-2} \cdot \text{K}^{-4}$ .

$T = 90 \; \textdegree{}\text{F} = (\dfrac{5}{9} \cdot (90-32) + 273.15) \; \text{K} = 305.372 \; \text{K}$ .

$\dfrac{P}{A} = \sigma \cdot T^{4} = 5.67 \times 10^{-8} \times 305.372^{4} = 493\; \text{W}\cdot \text{m}^{-2}$ .

Keep as many significant figures in $T$ as possible. The error will be large when $T$ is raised to the power of four. Also, the real value will be much smaller than $493\; \text{W}\cdot \text{m}^{-2}$ since the emittance of a human body is much smaller than assumed.

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3 years ago

Two rocks are at the top of a building. Rock 1 is dropped from rest while Rock 2 is thrown horizontaly at a velocity of 5 ms.

LuckyWell [14K]

Answer:

I'm pretty sure the answer is 0 m/s²

Explanation:

The horizontal velocity of the second rock is 5 m/s, so if we pretend air resistance doesn't exist, it will maintain that horizontal velocity, meaning that there is no horizontal acceleration.

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3 years ago

I need to know which ones are physical or chemical changes.

andrezito [222]

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I believe this is right but double check to make sure :)

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2 years ago

What is the difference between the number of electrons in an atom of selenium, Se, and the number of electrons in an atom of alu

Oxana [17]

Well, electrons can be converted into a atomic number so if SE atomic number is 34 that means it has 34 electrons. AI has a atomic number of 13 meaning it has 13 electrons.

So the difference is that SE has more electrons then AI.

Hope this helped. :D

4 0

3 years ago

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