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3 years ago

Question 2 (5 points)

Physics

1 answer:

Helen [10]3 years ago

5 0

Answer: A) All matter and energy were contained inside the small point.

Explanation: The theory that all matter and energy in the universe expanded from one condensed point (this is called the big bang theory) is the generally accepted explanation of the origins of our universe. Thought increasing amounts of doubt have been cast upon this theory in the last decade.

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A strong lightning bolt transfers an electric charge of about 31 C to Earth (or vice versa). How many electrons are transferred?

olchik [2.2K]

Answer:

$m=5.78\times 10^{-3}\ g$

$n_e=1.935\times 10^{20}$ is the no. of electrons

Explanation:

Given:

quantity of charge transferred, $Q=31\ C$

No. of electrons in the given amount of charge:

As we have charge on one electron $1.602\times 10^{-19}\ C$

so,

$n_e=\frac{Q}{e}$

$n_e=\frac{31}{1.602\times 10^{-19}}$

$n_e=1.935\times 10^{20}$ is the no. of electrons

Now if each water molecules donates one electron:

Then we require $n=1.935\times 10^{20}$ molecules.

Now the no. of moles in this many molecules:

$n_m=\frac{n}{N_A}$

where

$N_A=6.022\times 10^{23}$ Avogadro No.

$n_m=\frac{1.935\times 10^{20}}{6.022\times 10^{23}}$

$n_m=3.213\times 10^{-4}\ moles$

We have molecular mass of water as M=18 g/mol.

So, the mass of water in the obtained moles:

$n_m=\frac{m}{M}$

where:

m = mass in gram

$3.213\times 10^{-4}=\frac{m}{18}$

$m=5.78\times 10^{-3}\ g$

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3 years ago

It took 3.5 hours for a train to travel the distance between two cities at a velocity

Amiraneli [1.4K]

Answer:

420

Explanation:

420 because 120 x 3 = 360

120/2 = 60 and 360 + 60 = 420

I hope this helps you and please consider giving me brainliest :)

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3 years ago

What is a tool that measures the size of a force

MakcuM [25]

this is a dynamometer

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3 years ago

A car (mass = 1200 kg) is traveling at 31.1 m/s when it collides head-on with a sport utility vehicle (mass = 2830 kg) traveling

IrinaVladis [17]

Answer:

13.18 m/s

Explanation:

Let the velocity of sports utility car is

-u as it is moving in opposite direction.

mc = 1200 kg, uc = 31.1 m/s

ms = 2830 kg, us = - u = ?

Using conservation of momentum

mc × uc + ms × us = 0

1200 × 31.1 - 2830 × u = 0

u = 13.18 m/s

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3 years ago

According to the concept of punctuated equilibrium, _____.

STatiana [176]

According to the concept of punctuated equilibrium, new species evolve suddenly over relatively short periods of time (a few hundred to a thousand years), followed by longer periods in which little genetic change occurs. Hope this helps. Have a nice day.

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3 years ago