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Lera25 [3.4K]
3 years ago
7

Regarding the history of the universe, which of the following is true? Regarding the history of the universe, which of the follo

wing is true? Key elements of which Earth and life are made, including carbon, oxygen, and iron, did not exist when the universe was born and were created later in stars. All the chemical elements were created during the Big Bang, but some have been modified since that time as a result of radioactive decay. The Earth formed quickly after the Big Bang. All the current stars in our galaxy formed about the same time billions of years ago.
Physics
1 answer:
ale4655 [162]3 years ago
5 0

Explanation:

1. The universe consisted of hydrogen and helium initially. This statement is true.

2. It is important to understand radioactive decay in order to understand this question, here's a good analogy:

A snake will shed it's skin, just as an atom will shoot off different parts of itself. It would be very difficult to force that snake to reenter it's skin once it sheds, just as it takes a lot of energy to force <em>fusion</em><em> </em>of atoms and the parts mentioned. In normal circumstances, nuclear decay is one-way.

3. The earth is a giant floating rock in space. It took many many years to gather a bunch of asteroids and dust to make this planet.

4. I shouldn't have to explain this one, it doesn't make much sense.

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Gbenga needs to get glasses to correct his farsightedness. His eyes currently cannot focus on objects that are within 2 ft (or 6
Scilla [17]

Answer:

Focal Length = 38.61cm, Power = 2.59 Diopter, Converging lens.

Explanation:

When an object is placed 25cm from Gbenga's eye, the glasses lens must produce an image 61cm away (Gbenga's eye near point).

An image 61cm from the eye will be (61cm - 1.6cm) from the glasses.

i.e. d_{i}=61cm-1.6cm=59.4cm

and d_{o} = 25cm - 1.6cm = 23.4cm

note d_{i} will be negative because the image is formed on the same side as the object.

finally, d_{i}=-59.4cm\\d_{o}=23.4cm

the formula for finding the focal length f is given as

f=\frac{d_{i}d_{o}  }{d_{o}+d_{i}  }

f=\frac{-59.4*23.4}{23.4-59.4} \\

f=\frac{-1389.96}{-36}

f=38.61cm

The focal length is positive which indicates converging lens

power p=\frac{1}{f}

but f\\ must be in metres

Therefore, f=38.61cm=0.3861m

p=\frac{1}{0.3861}

p=2.59 Diopter

3 0
4 years ago
One student argues that a satellite in orbit is in free fall because the satellite keeps falling toward Earth.
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3 years ago
Using information about natural laws, explain why some car crashes produce minor injuries and others produce catastrophic injuri
kicyunya [14]
The forces in some car crashes are greater than others; therefore, the body can be more severely injured by greater and more powerful forces. I hope this helped! :^)
7 0
3 years ago
A cat with a mass of 5 kg sits on a branch that is 26 m off the ground. What is
Ostrovityanka [42]

Answer:

1274 J.

Explanation:

P. E= mgh

where m = 5 kg

g = 9.8m/s²

h = 26m

P. E = 5*26*9.8

=1274 J.

4 0
4 years ago
How long does a car (1000 kg) have a speed of 30 m/s from a rest if the engine power is 10kw
Lemur [1.5K]

Answer: 90.1 s

Explanation:

Use equation for power:

P=F*V

Use eqation for force:

F=ma

F---force

V---velocity

Vr=om/s

V=30m/s

m=1000kg

P=10000W

---------------------------

P=FV

F=P/V

F=10000W/30m/s

F=333.33N

Use equation for force to find accelartaion.

F=ma

a=F/m

a=333.33N/1000kg

a=0.333 m/s²

Use equation for accelaration to find out time:

a=(V-Vs)/t

t=(V-Vs)/a

t=(30m/s)/(0.333m/s²)

t=90.09 s≈90.1 s

------------------------

5 0
3 years ago
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