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kari74 [83]
3 years ago
13

What period did the first plants appear

Physics
2 answers:
deff fn [24]3 years ago
8 0

Answer:

Ordovician

Explanation:

r-ruslan [8.4K]3 years ago
4 0

Answer:

Ordovician: 470 million years ago

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The shape of an atom.is <br><br> Spherical<br> Square<br> Pyramifal
zvonat [6]
Spherical because it’s more like clouds
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3 years ago
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The aorta is the main artery from the heart. a typical aorta has an inside diameter of 1.8 cm and carries blood at speeds of up
defon

Answer:

Explanation:

Volume per unit time flowing   will be conserved

a₁v₁  = a₂ v₂

π r₁² x v₁ = π r₂² x v₂

(0.9 x 10⁻²)² x .35 = ( .45 x 10⁻² )² x v₂

v₂ = 1.4 m / s

3 0
3 years ago
If a cup of coffee has temperature 95∘C95∘C in a room where the temperature is 20∘C,20∘C, then, according to Newton's Law of Coo
lina2011 [118]

Answer:

T = 76.39°C

Explanation:

given,

coffee cup temperature = 95°C

Room temperature= 20°C

expression

T( t ) = 20 + 75 e^{\dfrac{-t}{50}}

temperature at t = 0

T( 0 ) = 20 + 75 e^{\dfrac{-0}{50}}

T(0) = 95°C

temperature after half hour of cooling

T( t ) = 20 + 75 e^{\dfrac{-t}{50}}

t = 30 minutes

T( 30 ) = 20 + 75 e^{\dfrac{-30}{50}}

T( 30 ) = 20 + 75 \times 0.5488

T(30) = 61.16° C

average of first half hour will be equal to

T = \dfrac{1}{30-0}\int_0^30(20 + 75 e^{\dfrac{-t}{50}})\ dt

T = \dfrac{1}{30}[(20t - \dfrac{75 e^{\dfrac{-t}{50}}}{\dfrac{1}{50}})]_0^30

T = \dfrac{1}{30}[(20t - 3750e^{\dfrac{-t}{50}}]_0^30

T = \dfrac{1}{30}[(20\times 30 - 3750 e^{\dfrac{-30}{50}} + 3750]

T = \dfrac{1}{30}[600 - 2058.04 + 3750]

T = 76.39°C

4 0
3 years ago
Which pairs of angles in the figure below are verticals angles ? check all that apply.
Dmitriy789 [7]

Answer:

mark two options:

B. TSN and ISW

D. ISN and TSW

Explanation:

Recall the definition of vertical angles as: <em>those angles opposed by the vertex, and which are the result of two lines that intersect</em>.

In the figure given there are two pairs such angles, one pair I depicted in red, and the other one in blue, while the intersecting lines are shown in green. Notice that when two lines intersect, there are always two pairs of vertical angles being generated.

Therefore, according to the notation given, two boxes need to be checked in the set of options:

1) the one corresponding to : TSN and ISW (blue ones in the attached image)

and

2) the one corresponding to ISN and TSW (red ones in the attached image)

5 0
3 years ago
Explain How is the frequency of a wave measured *
Ray Of Light [21]

Answer:

frequency of a wave can be measured by the number of crests in a second or more

6 0
3 years ago
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