why do we believe 90 percent of the mass of the milky way is in the form of dark matter?

Answers

Answer 1

Answer:

The orbital speeds of stars far from the galactic center are surprisingly high, suggesting that these stars are feeling gravitational effects from unseen matter in the halo.


Related Questions

Calculate the acceleration of a bottle rocket that is traveling at a speed of 74 m/s, and then descends at a speed of 89 m/s. It takes the rocket 5 seconds to change its speed.


a) 1 m/s/s


b) 2 m/s/s


c) 3 m/s/s


d) 4 m/s/s

Answers

Answer:Falling objects form an interesting class of motion problems. For example, we can estimate the depth of a vertical mine shaft by dropping a rock into it and listening for the rock to hit the bottom. By applying the kinematics developed so far to falling objects, we can examine some interesting situations and learn much about gravity in the process.

Explanation:


Why does the blue force have a negative sign?
-20 N
50 N
Because 50 is smaller than 20
Because 20 is smaller than 50
Because it is pointing to the left
Because it is blue

Answers

it’s B (because 20 Is smaller than 50)

Составьте правильное соответствие:
1. А. Лавуазье
А. Он говорил: «Знание – сила»
2. Д. Дальтон
Б. Изучал теорию газов.
3. Д.И. Менделеев
В. Опубликовал труд «Методы наименования химических элементов»
4. Р. Броун
Г. Работы посвящены морфологии и систематике растений.
5. М. Смолуховский
Д. Работы посвящены броуновскому движению.
6. Р. Бойль
Е. Ввел понятие «атомный вес»
7. Ф. Бэкон
Ж. Открыл периодический закон химических элементов.

Answers

1. good morning mam going to be a long day for me to be a long day for me to be a long day for me to be a long day for me to be a long day for me to be a long day for

An example of a conversation killer is?
making eye contact.
encouraging another person
talking about others
sharing your ideas and feelings

Answers

Answer: talking about others

How to calculate work in chemistry.

Answers

Answer:

look on the bottom

Explanation:

Is it only the math or the physics/physical concepts that you don't get?

In this problem, you have a constant pressure of 1.00 atm.  This being the case, it is an isobaric system (constant pressure), and so you have the equation that work (W) = -pressure(P) x change in volume (∆V)

This is written as W = -P∆V and is known as pressure-volume work.

Now, understand the conventions that are used.

-If work is done ON the system, it has a positive sign (+)

-If work is done BY the system, it has a negative sign (-)

In this problem, the gas is being compressed, i.e. the volume decreases, and so work is being done ON the system. Thus, the sign of W is positive (+).  This comes out automatically because of negative sign in front of P∆V,                                                                                                                                                                                           So,                                                                                                                                       we have W = -P∆V and substituting values, we have

W = -(1.00 atm)(1.5L - 1.25L) = -(1.00 atm)(0.25L) = -0.25 L-atm

Converting this to joules, we get -0.25 L-atm x 101.3 J/L-atm = -25.3 J (note the negative sign)                                                                                                    Hope this all helps a little.

A car traveling at 35.6m/s crashes into a concert barrier and comes to a stop in 0.35 seconds. Calculate the average force applied to the 75kg driver.A 3.2kg steel ball traveling at 4.1m/s strikes a second ball of a mass 2.3kg Initially at rest. Calculate the velocity of the second ball when the first one continues traveling in the same direction with a speed of 1.5m/s2 balls of putty are shot towards one another. Ball 1 has a mass of 4.3kg and is moving at 18.6m/s . Ball 2 has a mass of 5.8kg and is moving at 9.5m/s. They collide and stick together. Calculate their final combine velocity.I really appreciate those attempting the problems. I do know the answers but I’m unaware of the steps to get there. Please include all formulas in your response and steps so I can learn and understand.Check your answer:7629N3.6m/s2.46m/sThank you all!

Answers

The force on the driver is 7629 N. The velocity of the second ball is 3.6 m/s. The combined velocity of the balls is 13.37 m/s.

We have to find the acceleration using;

v = u - at

v = final velocity = 0 m/s

u = initial velocity = 35.6m/s

a = acceleration = ?

t = time = 0.35 s

u = at

a = u/t = 35.6m/s / 0.35 s

a = 101.7 ms-2

The force on the driver =  75kg ×  101.7 ms-2 = 7629 N

Using the principle of conservation of momentum;

Momentum before collision = momentum after collision

m1u1 +m2u2 = m1v1 + m2v2

Hence

(3.2 × 4.1) + 0 = (3.2 × 1.5) + 2.3v2

13.12 = 4.8 + 2.3v2

13.12 - 4.8 = 2.3v2

v2 = 13.12 - 4.8/2.3

v2 = 3.6 m/s

Using the principle of conservation of linear momentum;

m1u1 + m2u2 = m1v1 + m2v2

(4.3 × 18.6) + (5.8 × 9.5) = (4.3 + 5.8) v

v = 79.98 + 55.1/10.1

v = 13.37 m/s

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What happens when you want to move the boat forward? You pull the oars toward yourself.Explain why you do this.

Answers

Answer:

You pull on the oars. By the third law, the oars push back on your hands, but that’s irrelevant to the motion of the boat. The other end of each oar (the blade) pushes against the water. By the third law, the water pushes back on the oars, pushing the boat forward.

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A marble is launched at by dropping it through a marble launcher. The marble took 0.22s to land 0.31m from
where it was launched. Find the horizontal velocity of the marble as it rolls off the table.

A. 1.4m/s
B. 0.53m/s
C. 0.71 m/s
D. 0.07m/s

Answers

Hi there!

For projectile motion, the horizontal and vertical components are SEPARATE.

We can use the kinematic equation to solve:

dₓ = vₓt

We can rearrange to solve for vₓ:

dₓ/t = vₓ

0.31/0.22 = vₓ

vₓ = 1.4 m/s ⇒ A

when energy from battery was added to water, were the gases produced by this made of the same particles as those produced from heating the water?

Answers

Batteries often convert chemical energy directly to electrical energy.

From the experiment, the constructed conclusion was that;

The Two different gases with  different properties  are made from adding energy from a  battery to water.

The particles that make up these different  gases is different from each other. They  are different than the ones that were  made from heating water.  

The matter that is composed of  substances have to originate from matter that  made up some of the original water particles.

When energy from a battery is added to water, two streams of gas bubbles is said to be  produced. Then a lit match is put into  trapped gas from these two sources, one pops and the other glows brighter.

The study was to test the  flammability of gases produced by providing energy to water with electricity.

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A potted plant falls from the window of an apartment building. It falls for 2.0 s and then hits the ground. What is the speed of the plant just before it hits the
ground? Assume only gravity is acting on it.
A) 20m/s
B)9.8m/s
C)2.0m/s
D)4.9m/s

Answers

Answer:

D) 4.9 m/s

Explanation:

Speed of Object in Free Fall

s = Rate of Acceleration, Due to Gravity × Length of Time

s = 9.8 × 2.0

s = m/s (Round Up to The Nearest Whole Number)

--

m/s = 9.8 ÷ 2.0 = 4.9 m/s

What is equilibrium?​

Answers

Answer:

Balance is the ability to maintain body balance when placed in various positions.

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Hope it is Useful..

Answer:

A state of physical balance.

I hope this helps you!!!

What feature of a planet's orbit does Kelper's first law of motion describe?
A. the time required for each orbit
B. the shape
C. the distance from the aphelion to the perihelion
D. the distance to the sun

Answers

The answer is going to be letter B

what is the radius of the event horizon of a 10 solar mass black hole?

Answers

Answer:

The number take for the "radius" is normally taken to be the radius from the center to the event horizon, since nothing inside that can be observed, and since it is a point of no return. This radius is directly proportional to the mass of the black hole. From the Wikipedia article on event horizon: "For the mass of the Sun this radius is approximately 3 kilometers and for the Earth it is about 9 millimeters. In practice, however, neither the Earth nor the Sun has the necessary mass and therefore the necessary gravitational force, to overcome electron and neutron degeneracy pressure." The last sentence means that it is unlikely for the Sun to become a black hole, since it has too little mass to become one.

Explanation:

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Can someone help me with the entire magnetism gizmo. I can’t get on gizmo, but it has to be done

Answers

Answer:

sure how can i help my g gggg

Saima travels 2.5 km in 21.2 seconds. What as Saima's initial speed if her final velocity is 10.7 m/s?

Answers

Answer:

d/t = (230 km)/(3.25 h) = 70.8 km/h.

Explanation:

A student tested a variety of interacting forces to determine how they would result in motion of an object. If the student used the forces as shown in the lettered choices above, predict which results would occur. Select ALL that apply.A) The variable shown by letter B would result in a movement of the object to the left. B) The variable shown by letter B would result in a movement of the object to the right. C) The variable shown by letter A would result in a movement of the object to the right. D) The variable shown by letter C would result in a movement of the object to the right. E) The variable shown by letter D would result in a movement of the object

Answers

Answer:

A, D, C

Explanation:

consider the hypothetical observation irregular galaxies outside the local group are moving toward us. from part a, this observation would contradict the idea of an expanding universe. why?

Answers

Answer:

spiral galaxies move away from us 10% faster than elliptical galaxies at the same distances;  irregular galaxies outside the Local Group are moving toward us;  galaxy speeds are faster in summer than in winter

Explanation:

This may help I'm not sure.

is putting water in a water bottle increasing its mass?

Answers

Answer:

No

Explanation:

Answer:

yes

Explanation:

What is the given formula for acceleration?.

Answers

Answer:

a=v/t (searched)

Explanation:

a=acceleration

v=change in velocity

t=time

(searched)

please help I'm stuck on this question ​

Answers

Answer:

increase

decrease

Explanation:

using formula

Vt=mg/6πηr

so if m increases V increases

r is the denominator so if r increases V decreases

A balance and a graduated cylinder are used to determine the density of a mineral sample. The sample has a mass of 14. 7 g and a volume of 2. 2 cm3. What is the density of the mineral sample?.

Answers

D=M/V
so 14.7g/ 2.2 cm3 = Density
according my calculator this should be
3.23400 x 10 -8 m3

14.7g / 2.2cm3 = 3.23400 x 10 -8ms

Heat rising in a hot-air balloon is an example of __________.

Answers

Heat rising in a hot-air balloon is an example of convection.

A negative charge is paced in an electric field that points west. What direction is the force on the negative particle?

Answers

Answer:

A positive charge placed in an electric field will tend to move in the direction of the electric field lines and a negative charge will tend to move opposite to the direction of the electric field lines.

One way to remember this is that there is one velocity, and so the thumb represents it. There are many field lines, and so the fingers represent them. The force is in the direction you would push with your palm. The force on a negative charge is in exactly the opposite direction to that on a positive charge.

Explanation:

Answer:

The force of the negative particle direction is East.

Using your outline and the materials you’ve gathered, write a 500- to 750-word paper using word processing software. Be sure to proofread and revise your writing to catch any errors in grammar, spelling, logic, or organization. Add a works cited page at the end to give credit to your sources. Submit your completed paper along with this activity to your teacher for evaluation.

please do it based off of Werner Heisenberg the scientist.

Answers

Answer:

im half new how does this work

Explanation:

Answer:Werner Heisenberg was born on 5th December, 1901, at Wurzburg. He was the son of Dr. August Heisenberg and his wife Annie Wecklein. His father later became Professor of the Middle and Modern Greek languages in the University of Munich. It was probably due to his influence that Heisenberg remarked, when the Japanese physicist Yukawa discovered the particle now known as the meson and the term “mesotron” was proposed for it, that the Greek word “mesos” has no “tr” in it, with the result that the name “mesotron” was changed to “meson”.Heisenberg went to the Maximilian school at Munich until 1920, when he went to the University of Munich to study physics under Sommerfeld, Wien, Pringsheim, and Rosenthal. During the winter of 1922-1923 he went to Göttingen to study physics under Max Born, Franck, and Hilbert. In 1923 he took his Ph.D. at the University of Munich and then became Assistant to Max Born at the University of Göttingen, and in 1924 he gained the venia legendi at that University.From 1924 until 1925 he worked, with a Rockefeller Grant, with Nlels Bohr, at the University of Copenhagen, returning for the summer of 1925 to Göttingen.In 1926 he was appointed Lecturer in Theoretical Physics at the University of Copenhagen under Nlels Bohr and in 1927, when he was only 26, he was appointed Professor of Theoretical Physics at the University of Leipzig.In 1929 he went on a lecture tour to the United States, Japan, and India.In 1941 he was appointed Professor of Physics at the University of Berlin and Director of the Kaiser Wilhelm Institute for Physics there.At the end of the Second World War he, and other German physicists, were taken prisoner by American troops and sent to England, but in 1946 he returned to Germany and reorganized, with his colleagues, the Institute for Physics at Göttingen. This Institute was, in 1948, renamed the Max Planck Institute for Physics.In 1948 Heisenberg stayed for some months in Cambridge, England, to give lectures, and in 1950 and 1954 he was invited to lecture in the United States. In the winter of 1955-1956 he gave the Gifford Lectures at the University of St. Andrews, Scotland, these lectures being subsequently published as a book.During 1955 Heisenberg was occupied with preparations for the removal of the Max Planck Institute for Physics to Munich. Still Director of this Institute, he went with it to Munich and in 1958 he was appointed Professor of Physics in the University of Munich. His Institute was then renamed the Max Planck Institute for Physics and Astrophysics.

Every atom contains a
.............. which is positively charged

Answers

Answer:

Proton

Explanation:

The nucleus has an overall positive charge as it contains the protons. Every atom has no overall charge (neutral). This is because they contain equal numbers of positive protons and negative electrons.

How does the radius of a string affect centripetal force.

Answers

Answer:

because a raduis is half of 25% of a cicrle.

Explanation:

If an object is rolling without slipping, how is the speed of its center related to its angular velocity

Answers

Angular velocity w is directly proportional to its velocity.

Speed of its center will be directly proportional to its angular velocity in the case of rolling without slipping

 

What is rolling without slipping ?

Rolling without slipping is a combination of translation and rotation where the point contact is instantaneously at rest.                                                                                                                                                                                                                                                                                                                                                                

When an object rolls without slipping on an inclined plane , then the velocity of the center of mass will be equal to angular velocity times radius that object.

Vo = angular velocity * radius

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How do air particles move above a candle flame

Answers

It circulates. As warm air moves up, cooler air rushes in at the bottom of the flame. Once the cooler air is heated, it then rises up (like before) and is replaced by cooler air at the base of the flame.

Why is wrestling ring floor always softThis is physics

Answers

Answer:

So the people in the ring don't get hurt or break anything on impact once they hit the floor

What’s the mass of the continent?

Answers

Answer:

Assume that the north american continent can be respanterd by a slab of rock 4000 km on a side and 30 km deep and that the rock

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