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3 years ago

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Recently, the media, always trying to make things sound sensational, have started to call totally eclipsed moon "the blood moon.

" Why does the Moon look reddish to us when there is a total lunar eclipse?

1 answer:

Mariulka [41]3 years ago

6 0

Answer:

See explanation

Explanation:

- One meaning of a "blood moon" is based on its red glow. This blood moon occurs during a total lunar eclipse. During a total lunar eclipse, Earth lines up between the Moon and the Sun. This hides the Moon from the sunlight.

- When this happens, the only light that reaches the Moon's surface is from the edges of the Earth's atmosphere. The air molecules from Earth's atmosphere scatter out most of the blue light. The remaining light reflects onto the Moon's surface with a red glow, making the Moon appear red in the night sky.

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A plank rests on top of the axles of two identical wheels. Each wheel's outer radius is 0.25 meters and each wheel's axle has ra

kaheart [24]

Answer:

<u><em>The plank moves 0.2m from it's original position</em></u>

Explanation:

we can do this question from the constraints that ,

the wheel and the axle have the same angular speed or velocity
the speed of the plank is equal to the speed of the axle at the topmost point .

thus ,

<em>since the wheel is pure rolling or not slipping,</em>

<em>⇒ $v=wr$ </em>

where

<em> $v$ - speed of the wheel</em>

<em> $w$ - angular speed of the wheel</em>

<em> $r$ - radius of the wheel</em>

<em>since the wheel traverses 1 m let's say in time ' $t$ ' ,</em>

<em> $v_{w}=\frac{distance}{time} =\frac{1}{t}$ </em>

∴

⇒ $w=\frac{v_{w}}{r} = \frac{1}{t*0.25}$

the speed at the topmost point of the axle is :

⇒ $v_{a}=w*r\\v_{a}=\frac{1}{t*0.25} *0.05\\v_{a}=\frac{1}{5t}$

this is the speed of the plank too.

thus the distance covered by plank in time ' $t$ ' is ,

⇒ $d=v_{a}*t\\d=\frac{1}{5t} *t\\d=\frac{1}{5} = 0.2m$

8 0

3 years ago

Loudspeakers can produce intense sounds with surprisingly small energy input in spite of their low efficiencies. Calculate the p

Dennis_Churaev [7]

Answer:

$5.87*10^{-4}W$

Explanation:

Given that:

$\beta = 89,6 dB$

$D = 13.0 cm$

$r = \frac{D}{2}\\ = \frac{13.0}{2}\\ = 6.5 cm\\=0.065m$

Efficiency = 2.06 % = 0.0206

The intensity level of sound is given by the formula:

$\beta = (10dB) log (\frac{I}{I_o} )$

$\frac{\beta}{(10dB) } =log (\frac{I}{I_o} )$

Taking their exponential; we have :

$10^{\frac{\beta}{10dB}}= \frac{I}{I_o}$

$I = I_o(10^{\frac{\beta}{10dB}})$

Replacing our values; we have:

$I = (10^{-12}W/m^2)(10^{\frac{89.6}{10dB}})$

$= 9.12 *10^{-4}W/m^2$

Power Output;

$P_{out} = IA\\P_{out}=I(\pi r^2)\\P_{out}=(9.12*10^{-4}W/m^2)(3.14)(0.065m)^2\\P_{out}=1.2099048*10^{-5} W$

The power output that is required to produce a 89.6 dB sound intensity level for a 13.0 cm diameter speaker that has an efficiency of 2.06% is;

$P_{in}= \frac{P_{out}}{0.0206}$

$P_{in}= \frac{{1.2099048*10^{-5}}}{0.0206}$

$P_{in}= 5.87*10^{-4}W$

Therefore, The power output that is required to produce a 89.6 dB sound intensity level for a 13.0 cm diameter speaker that has an efficiency of 2.06% is $5.87*10^{-4}W$

8 0

3 years ago

Given a force of 56 N and an acceleration of 7 m/s2, what is the mass?

love history [14]

Answer:

<h2>8 kg</h2>

Explanation:

The mass of an object can be found by using the formula

$m = \frac{f}{a} \\$

f is the force

a is the acceleration

From the question we have

$m = \frac{56}{7} \\$

We have the final answer as

<h3>8 kg</h3>

Hope this helps you

6 0

3 years ago

When white light is incident on a prism, which one of the resulting color components will have the lowest index of refraction?

soldi70 [24.7K]

Blue has the lowest index of refraction

3 0

2 years ago

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Which of the following is an example of a density-independent factor limiting population growth

Lisa [10]

The appropriate response is the Unusual climate. These are eccentric serious or unseasonal climate; climate at the extremes of the authentic circulation—the range that has been found before. Regularly, extraordinary occasions depend on an area's recorded climate history and characterized as lying in the most strange 10%.

6 0

3 years ago