Ask question

Ask question

All categories

sleet_krkn [62]

3 years ago

6

Recently, astronomers have observed stars and other objects that orbit the center of the Milky Way Galaxy farther out than our S

un, but move around faster than we do. How do astronomers think such an observation can be explained?

1 answer:

Lesechka [4]3 years ago

7 0

Answer:

That scenario can be explained by the idea of the contribution of dark matter on that point.

Explanation:

It can be explained through the idea of dark matter, this one was born to explain why stars (or any object) that were farther for the supermassive black hole in the center of the Milky Way galaxy didn't decrease it rotational velocity as it was expected according to equation 1.

$v = \sqrt{\frac{G M}{r}}$ (1)

Where v is the rotational velocity, G is the gravitational constant, M is the mass of the supermassive black hole, and r is the orbital radius.

Notice, that If the distance increases the orbital speed decreases (inversely proportional).

You might be interested in

Because ions in an ionic crystal are tightly bound together, _____. it takes little energy to change them from a solid to a liqu

umka2103 [35]

Ions are particles formed when an atom of an element looses or gains electrons to attain a stable configuration.They are either positively charged (cations) or negatively charged (anions). Ionic crystals consists of ions bound together by electrostatic attraction forming a regular arrangement, geometric structure called crystal lattice. In an ionic solid the ions are held by strong attractive forces (tightly bound) and cannot move from their positions in the crystal structure and therefore, do not conduct electricity.

7 0

3 years ago

It takes 23 seconds to hoist a rescue diver of mass 80 kg from the ocean surface to a helicopter hovering 23.9 meters above the

tino4ka555 [31]

Answer:

840 W

Explanation:

The energy expended in hoisting the diver up is given by

$E = mgh$

<em>m</em> is the mass of the diver, <em>g </em>is the acceleration due to gravity and <em>h</em> is the height.

Using the values in the question and taking <em>g</em> as 9.8 m/s²,

$E = (80\text{ kg})\times (9.8\text{ m/s}^2)\times (23.9\text{ m}) = 18737.6\text{ J}$

The power is given by

$P = \dfrac{E}{t}$

<em>t</em> is the time.

Hence,

$P = \dfrac{18737.6\text{ J}}{23\text{ s}} = 841.678\ldots \text{ W}\approx 840\text{ W}$

4 0

3 years ago

Two motors in a factory are running at slightly different rates. One runs at 825.0 rpm and the other at 786.0 rpm. You hear the

mixas84 [53]

Answer:

$T=1.54s$

Explanation:

From the question we are told that:

Speed of Motor 1 $\omega_1=825rpm=>2 \pi 13.75$

Speed of Motor 2 $\omega_1=786rpm=>2 \pi 13.1$

Therefore

Frequency of Motor 1 $f_1=13.75$

Frequency of Motor 2 $f_2= 13.1$

Generally the equation for Time Elapsed is mathematically given by

$T=\frac{1}{df}$

Where

$df=f_1-f_2$

$df=13.75-13.1$

$df=0.65Hz$

Therefore

$T=\frac{1}{65}$

$T=1.54s$

5 0

3 years ago

A current of 6.93 A 6.93 A in a long, straight wire produces a magnetic field of 4.15 μT 4.15 μT at a certain distance from the

natka813 [3]

Answer:

0.334 m

Explanation:

The magnetic field due to current in a straight thin wire, $B$ , is given by

$B = \dfrac{\mu_0 I}{2\pi R}$

where $\mu_0$ is the permeability of free spave with value $4\pi\times10^{-7}$ and $R$ is the distance from the wire.

$R = \dfrac{\mu_0 I}{2\pi B}$

Substituting the values from the question,

$R = \dfrac{4\pi\times10^{-7}\times 6.93}{2\pi\times 4.15\times 10^{-6}}$

$R = \dfrac{2\times10^{-1}\times6.93}{4.15} = 0.334 \text{ m}$

7 0

4 years ago

Read 2 more answers

The gravity tractor, is a proposed spacecraft that will fly close to an asteroid whose trajectory threatens to impact the Earth.

Crazy boy [7]

Answer:

$F_g=461lb_f$

Explanation:

First calculate the mass of the asteroid. To do so, you need to find the volume and know the density of iron.

If r = d/2 = 645ft, then:

$V = \frac{4}{3} \pi r^3$

$V = \frac{4}{3} \pi r^3\\V = 1.124\times10^{9}ft^3\delta_{iron}=m/V=491lb/ft^3m=V\times\delta=5.519\times10^{11}lb$

In order to find force, use Newton's universal law of gravitation:

$F_g=G\frac{m_1m_2}{d^2}$

Where,

G= the gravitational constant:

$G= 1.068846 \times10^{-9} ft^3 lb^{-1} s^{-2}$

$F_g=461lb_f$

4 0

3 years ago