Are sharks endangered from natural selection or artificial selection or both?

why is a person who lives in the city able to sleep through the sounds of traffic but awaken to the soft sound of bird singing

mash [69]

They grew up to that sound. They love the sound of that same traffic sound.

5 0

3 years ago

Read 2 more answers

How is lightning related to static electricity?

Naily [24]

Lighting is the static electricity stored in the clouds that is disposed to the earth.

8 0

3 years ago

Two massless bags contain identical bricks, each brick having a mass M. Initially, each bag contains four bricks, and the bags m

stepladder [879]

Answer: $F_{2}=\frac{3}{4}F_{1}$

Explanation:

According to Newton's law of universal gravitation:

$F=G\frac{m_{1}m_{2}}{r^2}$

Where:

$F$ is the module of the force exerted between both bodies

$G$ is the universal gravitation constant.

$m_{1}$ and $m_{2}$ are the masses of both bodies.

$r$ is the distance between both bodies

In this case we have two situations:

1) Two bags with masses $4M$ and $4M$ mutually exerting a gravitational attraction $F_{1}$ on each other:

$F_{1}=G\frac{(4M)(4M)}{r^2}$ (1)

$F_{1}=G\frac{16M^2}{r^2}$ (2)

$F_{1}=16\frac{GM^2}{r^2}$ (3)

2) Two bags with masses $2M$ and $6M$ mutually exerting a gravitational attraction $F_{2}$ on each other (assuming the distance between both bags is the same as situation 1):

$F_{2}=G\frac{(2M)(6M)}{r^2}$ (4)

$F_{2}=G\frac{12M^2}{r^2}$ (5)

$F_{2}=12\frac{GM^2}{r^2}$ (6)

Now, if we isolate $\frac{GM^2}{r^2}$ from (3):

$\frac{F_{1}}{16}=\frac{GM^2}{r^2}$ (7)

Substituting $\frac{GM^2}{r^2}$ found in (7) in (6):

$F_{2}=12(\frac{F_{1}}{16})$ (8)

$F_{2}=\frac{12}{16}F_{1}$ (9)

Simplifying, we finally get the expression for $F_{2}$ in terms of $F_{1}$ :

$F_{2}=\frac{3}{4}F_{1}$

5 0

3 years ago

A well is being dug. A 4.5-kg bucket is filled with 28.0 kg of dirt and pulled vertically upward at a constant speed through a d

andreyandreev [35.5K]

The work done on the filled bucket in raising out of the hole is 2, 925 Joules

<h3>How to determine the work done</h3>

Using the formula:

Work done = force * distance

Note that force = mass * acceleration

F = mg + ma

F = 4. 5 * 10 + 28 * 10

F = 45 + 280

F = 325 Newton

Distance = 9m

Substitute into formula

Work done = 325 * 9

Work done = 2, 925 Joules

Therefore, the work done is 2, 925 Joules

Learn more about work done here:

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4 0

2 years ago

Which is brighter in our sky, a star with apparent magnitude 2 or a star with apparent magnitude 7?

Lina20 [59]

The star with apparent magnitude 2 is more brighter than 7.

To find the answer, we have to know about apparent magnitude.

<h3>What is apparent magnitude?</h3>

100 times as luminous as a star with an apparent brightness of 7 is a star with a magnitude of 2.
The apparent magnitude of bigger stars is always smaller.
The brightest star in the night sky is Sirius.
The brightness of a star or other celestial object perceived from Earth is measured in apparent magnitude (m).
The apparent magnitude of an object is determined by its inherent luminosity, its distance from Earth, and any light extinction brought on by interstellar dust in the path of the observer's line of sight.

Thus, we can conclude that, the star with apparent magnitude 2 is more brighter than 7.

Learn more about the apparent magnitude here:

brainly.com/question/350008

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7 0

1 year ago