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4 years ago

What are the four theories of the origin of the moon?

2 answers:

8 0

1. Fission theory - Earth may have been spinning so fast that a part of our planet may have spun off into space, but kept tethered by Earth’s gravity.
2. Capture theory - the moon originated elsewhere in the Milky Way.
3. Co-accretion theory - The moon and the Earth formed together when orbiting a black whole.
4. Giant impact hypothesis - A planetary object impacted Earth, causing a portion of the plant to come off and become the moon.

poizon [28]4 years ago

8 0

1. Fission theory
2.capture theory
3. Co-accretion theory
4. Giant impact hypothesis

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The air in a room with volume 180 m3 contains 0.25% carbon dioxide initially. fresher air with only 0.05% carbon dioxide flows i

Butoxors [25]

Answer:

$p(t)=\frac{1}{20}(1+2e^{-t/90})$

Explanation:

Let $p(t)$ be % of $CO_2$ at time $t$ (time in minutes).

Amount of $CO_2$ in room=Volume of room $\times p$

Rate of change of $CO_2$ in room=Volume of room x $\frac{dp}{dt}$

$=180\times \frac{dp}{dt}$

Rate of inflow of $CO_2$ = $(\% CO_2 \ in\ Fresh\ Air \times \frac{1}{100})\times(Rate \ of Inflow\ of \ air)$

$=(0.05\times \frac{1}{100})\times 2=\frac{1}{100}$

Rate of $CO_2$ outflow

$(\% CO_2 \ in\ Fresh\ Air \times \frac{1}{100})\times(Rate \ of Outflow\ of \ air)\\=(p\times\frac{1}{100})\times2=\frac{p}{50}$

Therefore rate of change of $CO_2$ is $\frac{1}{100}-\frac{p}{50}$

% rate of change is $100\times \ Rate of \ Change=\frac{1}{10}-2p$

Therefore we have:

$180\frac{dp}{dt}=\frac{1}{10}-2p\\\frac{dp}{dt}=\frac{1-20p}{1800}\\\\\frac{dp}{20p-1}=-\frac{dt}{1800}$

Integrate both:

$\int\limits \frac{dp}{20p-1}=\int\limits-\frac{dt}{1800}$

$\frac{1}{20}In|20p-1|=-\frac{t}{1800}+In \ C$

In $|20p-1|=-\frac{t}{90}+$ In $K$

$+20In \ C=+In \ K$

Raise both sides to base $e$ ,

$20p-1=e^{-\frac{t}{90}+In \ K}\\\\p=\frac{1}{20}(1+Ke^{-t/90})$

Initially, there's only 0.25% of $CO_2$ ,

Now substitute $p=0.25$ and $t=0$

$0.25=\frac{1}{20}(1+K)\\K=4$

$p=\frac{1}{20}(1+2e^{-t/90})$

8 0

3 years ago

Use vector notation to describe the points that lie in the configuration. (Let s and t be elements of the Reals). the plane span

aniked [119]

Answer:

The answer is l(s, t) = (2s,7s + 2t,7t)

Explanation:

A general vector notation that can describe the points which lie in the configuration of the plane spanned by v1 and v2, is evaluated, thus:

V = v1 + v2

Where s and t are the elements of v1(2,7,0) and v2(0,2,7), respectively, and projected in x, y and z coordinates, we have:

V = sv1 + sv2, implying that:

V = (2sx + 7sy + 0sz) + (0tx + 2ty + 7tz)

Or, V= (2sx + 7sy) + (2ty + 7 tz)

Therefore, V = (2s,7s + 2t,7t)

and l(s, t) = (2s,7s + 2t,7t).

5 0

3 years ago

Find the mass of a child who runs at a speed of 4 m/s to get a pizza with extra cheese. His momentum is 120 kg•m/s.

tamaranim1 [39]

Wow! Very simple. Use the equation for momentum which is p=mv. You know your momentum and velocity, so do 120=m(4), now solve for m, which is 30. The mass of the child is 30 kg

7 0

3 years ago

A block slides on a frictionless, horizontal surface with a speed of 1.32 m/s. The block encounters an unstretched spring and co

Rus_ich [418]

Answer:

Explanation:

The given time is 1 / 4 of the time period

So Time period of oscillation.

= 4 x .4 =1.6 s

When the block reaches back its original position when it came in contact with the spring for the first time , the block and the spring will have maximum

velocity. After that spring starts unstretching , reducing its speed , so block loses contact as its velocity is not reduced .

So required velocity is the maximum velocity of the block while remaining in contact with the spring.

v ( max ) = w A = 1.32 m /s.

3 0

4 years ago

A wave with a wavelength of 69 meters has a period of 13 seconds. What is the speed of the wave?

Elza [17]

4 0

4 years ago

Read 2 more answers