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3 years ago

Dark matter may explain _____.

Physics

2 answers:

tia_tia [17]3 years ago

5 0

Answer: A.unexpected orbital velocities of stars in galaxies

Explanation:

Dark Matter makes up about 80% of matter in the universe. This matter does not emit light and hence, it is called dark matter as it cannot be observed directly.

The effect of the presence of the dark matter is unexpected orbital velocities of stars in galaxies. At the center, the orbital velocities are greater than those at the edge. Had there been no dark matter, the galaxy would have flown apart.

Lisa [10]3 years ago

4 0

Dark matter may explain <span>unexpected orbital velocities of stars in galaxies.</span>

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A long coaxial cable consists of an inner cylindrical conductor with radius a and an outer coaxial cylinder with inner radius b

Natasha_Volkova [10]

Answer:

Part a)

$E = \frac{\lambda}{2\pi \epsilon_0 r}$

Part b)

$E = \frac{\lambda}{2\pi \epsilon_0 r}$

Part d)

As we know that due to induction of charge there will be same charge appear on the inner and outer surface of the cylinder but the sign of the charge must be different

On the inner side of the cylinder there will be negative charge induce on the inner surface and on the outer surface of the cylinder there will be same magnitude charge with positive sign.

Explanation:

Part a)

By Guass law we know that

$\int E. dA = \frac{q}{\epsilon_0}$

$E. 2\pi rL = \frac{\lambda L}{\epsilon_0}$

$E = \frac{\lambda}{2\pi \epsilon_0 r}$

Part b)

Outside the outer cylinder we will again use Guass law

$\int E. dA = \frac{q}{\epsilon_0}$

$E. 2\pi rL = \frac{\lambda L}{\epsilon_0}$

$E = \frac{\lambda}{2\pi \epsilon_0 r}$

Part d)

As we know that due to induction of charge there will be same charge appear on the inner and outer surface of the cylinder but the sign of the charge must be different

On the inner side of the cylinder there will be negative charge induce on the inner surface and on the outer surface of the cylinder there will be same magnitude charge with positive sign.

4 0

3 years ago

What simple machines combine to make a shovel which is a compound

IRINA_888 [86]

B) lever and pulley is the answer

6 0

3 years ago

Which of the following statements are true?Check all that apply.

MaRussiya [10]

Answer:

1.The Sun is located at one of the foci of the planets' elliptical orbits.

2.The path of the planets around the Sun is elliptical in shape.

Explanation:

As per Kepler's law of planet motion we know that all planets revolve around the sun in elliptical path in such a way that position of Sun must be at one of the focii of the path

So all planets are in elliptical path always

Position of sun is always at one of the focus

so correct answer will be

1.The Sun is located at one of the foci of the planets' elliptical orbits.

2.The path of the planets around the Sun is elliptical in shape.

4 0

3 years ago

In the fusion reaction occurring in the Sun, how does the mass of helium atom formed compare to the mass of the hydrogen atoms?

PolarNik [594]

B bc there is a lot of hydrogen used