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3 years ago

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What is Precambrian time?

1 answer:

Ilia_Sergeevich [38]3 years ago

3 0

Answer:

The Precambrian Era comprises all of geologic time prior to 600 million years ago. The Precambrian was originally defined as the era that predated the emergence of life in the Cambrian Period.

Explanation:

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A plane stops from 250 mph in 25 seconds. Calculate the plane's acceleration.

Lelechka [254]

Explanation:

Given:

v₀ = 250 mph

v = 0 mph

t = 25 s

Find: a

v = at + v₀

(0 mph) = a (25 s) + (250 mph)

a = -10 mph/s

6 0

2 years ago

The three forces acting on a hot-air balloon that is moving vertically are its weight, the force due to air resistance and the u

irinina [24]

Explanation :

The forces acting on hot- air balloon are:

Weight, (W)

Force due to air resistance, (F)

Upthrust force, (U)

Its weight W is acting in downward direction. The upthrust force U acts in upward direction. When the balloon is moving upward, the air resistance is in downward and vice versa.

In this case, the hot-air balloon descends vertically at constant speed.

so, $a=0$

and $F=ma=0$

so, $W = F + U$ ....................(1)

when it is ascending let the weight that it is releasing is R, so

$(W-R) + F = U$ ..........(2)

solving equation (1) and (2)

$(W-R)+F=W-F$

$R=2F$

2F is the weight of material that must be released from the balloon so that it ascends vertically at the same constant speed.

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2 years ago

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The force diagram represents a girl pulling a sled with a mass of 6.0 kg to the left with a force of 10.0 N at a 30.0 degree ang

STatiana [176]

the correct answers are 54N and -1,2m/s^2

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2 years ago

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Which statement best describes how the temperature of the oceans surface water varies

lorasvet [3.4K]

If the temperature is high there is less water because it evaporates if it is cloudy it is more because it doesn't evaporate

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3 years ago

Now, find the concentration of H+ ions to OH– ions listed in Table B of your Student Guide for a solution at a pH = 11. Then div

Hunter-Best [27]

Answer

1.0/5

4

IlaMends

Ambitious

2.1K answers

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Explanation:

When pH of the solution is 11.

..(1)

At pH = 11, the concentration of ions is .

When the pH of the solution is 6.

..(2)

At pH = 6, the concentration of ions is .

On dividing (1) by (2).

The ratio of hydrogen ions in solution of pH equal to 11 to the solution of pH equal to 6 is .

Difference between the ions at both pH:

This means that Hydrogen ions in a solution at pH = 7 has ions fewer than in a solution at a pH = 6

8 0

2 years ago

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