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3 years ago

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This problem has been solved!See the answerCommunication with submerged submarines via radio waves is difficult because seawater

is conductive and absorbs electromagnetic waves. Penetration into the ocean is greater at longer wavelengths, so the United States has radio installations that transmit at 76Hz for submarine communications.What is the approximate wavelength of those extremely low-frequency waves?500 km1000 km2000 km4000 km

1 answer:

mash [69]3 years ago

8 0

Answer:

4000 km

Explanation:

as we know velocity of electromagnetic wave is c

$c = 3 * 10^8 m/s$

frequency given (f) = 76 Hz

wavelength ?

using

$c =f$ λ

λ = $\frac{c}{f}$

λ = $\frac{3 * 10^8}{76}$ ≈4000 km

so final answer λ = 4000km

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When the distance between two stars decreases by one-third, the force between them

pashok25 [27]

Answer:

the force will increase by a factor 2.25

Explanation:

The gravitational force between the two stars is given by:

$F=G\frac{m_1 m_2}{r^2}$

where

G is the gravitational constant

m1, m2 are the masses of the two stars

r is the distance between the stars

If the distance is decreased by one-third, it means that the new distance is 2/3 of the previous distance

$r'=\frac{2}{3}r$

So the new force will be

$F'=G\frac{m_1 m_2}{(\frac{2}{3}r)^2}=\frac{9}{4} G\frac{m_1 m_2}{r^2}=2.25 F$

So, the force will be 2.25 times the previous value.

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3 years ago

nsider a common mirage formed by superheated air immediately above a roadway. A truck driver whose eyes are 2.00 m above the roa

Anna11 [10]

Answer:

$n_{air} =1.0000355$

Explanation:

from snells law we have following relation

$n' Sin i = n_{air} Sin r$

$
n_{air}$ is refractive index of air

n' - refractive index of air below

i is angle of incidence = 90 - 1.30 = 88.70^o

r is refraction angle

plugging all value in above formula

$1.000293 \times sin 88.7 = n_{air} \times sin 90$

$n_{air} =1.0000355$

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3 years ago

How do your shoe laces relate to a pulley

Margarita [4]

The grommets on your shoe (Holes through which you place the lace) act as the pulley. When you tighten at the top it restricts at the bottom and compresses around your foot.

The same can be applied to a pulley; If you have the proper set up Pulling one string causes two actions; the first being the most obvious. And the second being its effect. The Grommets of your shoe are the pulley's; while your Shoelaces are just the rope with which you operate the pulley.

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3 years ago

A 10-kg disk-shaped flywheel of radius 9.0 cm rotates with a rotational speed of 320 rad/s. Part A Determine the rotational mome

Leya [2.2K]

Answer:

(A). The rotational momentum of the flywheel is 12.96 kg m²/s.

(B). The rotational speed of sphere is 400 rad/s.

Explanation:

Given that,

Mass of disk = 10 kg

Radius = 9.0 cm

Rotational speed = 320 m/s

(A). We need to calculate the rotational momentum of the flywheel.

Using formula of momentum

$L=I\omega$

$L=\dfrac{1}{2}mr^2\omega$

Put the value into the formula

$L=\dfrac{1}{2}\times10\times(9.0\times10^{-2})^2\times320$

$L=12.96\ kg m^2/s$

(B). Rotation momentum of sphere is same rotational momentum of the flywheel

We need to calculate the magnitude of the rotational speed of sphere

Using formula of rotational momentum

$L_{sphere}=L_{flywheel}$

$I\omega_{sphere}=I\omega_{flywheel}$

$\omega_{sphere}=\dfrac{I\omega_{flywheel}}{I_{sphere}}$

$\omega_{sphere}=\dfrac{I\omega_{flywheel}}{\dfrac{2}{5}mr^2}$

Put the value into the formula

$\omega_{sphere}=\dfrac{12.96}{\dfrac{2}{5}\times10\times(9.0\times10^{-2})^2}$

$\omega_{sphere}=400\ rad/s$

Hence, (A). The rotational momentum of the flywheel is 12.96 kg m²/s.

(B). The rotational speed of sphere is 400 rad/s.

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3 years ago

What is the acceleration of a 25 kg mass pushed by a force of 5 N?

Katyanochek1 [597]

Acceleration = force/mass
f=5
m=25
5/25 = 0.2

4 0

3 years ago

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