All categories

3 years ago

Hubble's law states that

Physics

1 answer:

Maslowich3 years ago

5 0

Answer:

Option (B)

Explanation:

According to Hubble's law, the distance from the earth to the distant galaxies is directly proportional to their recessional velocity (redshift). This means that the more is the distance between the earth and a galaxy, the faster the galaxy is moving away from the earth.

Recessional velocity normally refers to the speed or velocity at which any astronomical body such as a planet, asteroid, star or galaxy moves away from a reference point, such as from earth.

Thus, the correct answer is option (B).

You might be interested in

If you were to walk at a constant speed 20m/s for 30 seconds, how far would you walk?

lana [24]

Answer:

600m

Explanation:

30×20 at a constant speed is 600m.

6 0

4 years ago

Which of the following statements are true?

lukranit [14]

Answer:

The following statements are true:

1) A positive charge and a negative charge attract each other.

2) Electric charge is conserved.

3) A neutral object contains no charge.

4) Two negative charges repel each other.

5) Electric charge is quantized.

Explanation:

1) Experimentally, it has been showed that there are two types of charges (arbitrarily defined as positiva and negative), and that there exists a force between them, being attractive between opposite types of charges.

2) The charge is a fundamental property of matter, and like energy, must be always conserved. It can't neither be created nor destroyed.

3) A neutral object contains no net charge, being equal the number of positive and negative charges in it, so they counteract each other, being the net effect null, so it is said that the object is neutral.

4) As stated in (1) , there exists two types of charges, and it had been experimentally found that charges of the same type repel each other, so two negative charges repel each other.

5) Any charge is ultimately a set of electrons and/or protons, so it is always a multiple of the elementary charge carried by one of them, equal to 1.6*10⁻¹⁹ coulombs (unit of electric charge), so we can conclude that the charge is quantized.

8 0

3 years ago

Help on the second part please (b)

Oksanka [162]

I'll do that with pleasure. But first, we seriously need to discuss part-A.
The answer to part-A is used to solve part-B, and you don't have it yet.

I loved the way you set up part-A ... started out with the formula you'll use
to solve it, then listed the given information neatly, and substituted the given
information into the formula. All of that was so beautifully laid out ... with
units and everything, which hardly anybody ever does ... that I didn't notice
the absurd result at first.

Angie ! Take two steps back and look over part-A ! You multiplied
(200 and something) by (100 and something), and got an answer of
(200 and something) ! What's up with that ? ! ?

Everything outside the box is correct and beautiful ... units and everything.
Inside the box should be 30,021 kg-m/s .

NOW we're equipped to work on part-B:

You start out with F = m a .
That's the best formula to use for roughly 99.9% of these motion problems ...
but not for this one, sadly.

Here's what you need for part-B. Again, I love the way you start out listing
the formula you're going to use, and all the data you know.
But I think the whole subject of 'Impulse' temporarily slipped your mind.
Here's a quick review:

-- (force) acting for (some limited time) is called "Impulse".
-- The magnitude of impulse is (force) x (time).
-- Impulse is a vector. The direction of impulse is the direction of the force.
-- Look at the units. (I wouldn't do this with anyone else, but you're different ...
you have an understanding and appreciation for units.)

force = 'newton' = kg-m/s²
time = second

Impulse = (force) · (time)

      = (kg-m/s²) · (sec) = kg-m/s . Same units as momentum !

It turns out that the amount of impulse is exactly the amount of
change in momentum !

You push on an object with (some force) for (some time).
Then you stop pushing and you let the object go on its way.
The impulse you delivered to the object is (force) x (time), and that's
exactly how much momentum you gave it !

NOW ... The motorcycle has 30,021 kg-m/s of momentum.
In order to stop it ...
that's how much momentum it needs to lose.
OR
that's how much impulse you have to give it, opposite to its motion.

   (Force) x (time) = 30,021 kg-m/s

Divide each side
by t = 0.05 sec: Force    = (30,021 kg-m/s) / (0.05 sec)

= (30,021 / 0.05) kg-m/s²

=    600,423 newtons

(roughly 135,000 pounds)

(That's why a motorcycle crash
   can often mess up your hair.
   Or worse. )

4 0

3 years ago

Sunspots change in number and location during the solar cycle. This phenomenon is connected to

skad [1K]

Answer:

Continuously changing magnetic field of the Sun

Explanation:

The Sun is made up of plasma and is not solid like our planet. When it rotates the whole of the Sun doesn't rotate with same speed. The equatorial part completes the rotation in just 25 days whereas the poles do it in 35 days. Due to this the magnetic field lines entangle and reorganize them regularly.

The places where the field line exit and enter the surface of the Sun, temperature drops by around 1000 K thus these spots appear black in color and are known as Sun spots.

The magnetic field is not permanent as it will keep changing due to differential rotation. This will result in the change in the no. of location of Sun spots.

If we track the no. of sunspots visible with respect to years we will notice that they follow a cycle of 10.6 years. This is known as Solar cycle in which there comes a solar minima when we see very few sunspots. When it is solar maxima we can see more than 100 sunspots.

8 0

3 years ago

Light whose wavelength is 633nm falls on a double slit with spacing of 0.100mm. What is the separation between the 0th and 1st o

Over [174]

Answer:

Approximately 0.00760 m (that's 7.60 mm.)

Explanation:

Refer to the first diagram attached. For a double-slit diffraction, the angle (angular separation) between the m-th maximum and the central maximum satisfies the following equation:

$\displaystyle \sin{\theta} = \frac{m\cdot \lambda}{d}$ , where