If we aim a radio telescope at a distant spiral arm of the Milky Way Galaxy, we will probably observe a 21-cm line. If we point a large optical telescope at this same region, we will probably not be able to detect the neutral hydrogen that gives rise to the 21-cm radio signal. Why not

Answers

Answer 1

Answer:

Because of the interstellar dust and interior location of the solar system.

Explanation:

We will probably not be able to detect the neutral hydrogen that gives rise to the 21-cm radio signal if we point a large optical telescope to the region because, the interstellar dust obscures the location of the spiral arm of the Milky way galaxy and this makes neutral hydrogen that gives rise to the 21-cm radio signal difficult to detect.

Also, the interior location of the solar system also makes the neutral hydrogen that gives rise to the 21-cm radio signal difficult to detect.

So, the interstellar dust and the interior location of the solar system makes it difficult to detect the neutral hydrogen that gives rise to the 21-cm radio signal with a large optical telescope.


Related Questions

steel wire 8m long and 4mm in diameter is fixed to two rigid b. [1] supports. Calculate the increase in tension when the temperature falls by 10°C. Given linear expansivity of steel, a 12x10 %/K, Young's modulus for steel, Y = 2x10¹¹ N/m².​

Answers

Answer:

301.6 N

Explanation:

The length of the wire L₀ = 8 m and its diameter, d = 4 mm = 4 × 10⁻³ m. Since its temperature drops by  10°C, it will have a change in length ΔL = L₀αΔθ where α = linear expansivity of steel, a 12 × 10⁻⁶ /K, and Δθ = temperature change = -10°C = -10 K(negative since it is a drop)

So, the strain, ε = ΔL/L₀ = αΔθ = 12 × 10⁻⁶ /K × 10 K = 12 × 10⁻⁵

Now the Young's modulus of steel, Y = σ/ε where σ = stress = T/A where T = increase in tension in steel wire and A = cross-sectional area of wire = πd²/4 where d = diameter of wire = 4 × 10⁻³ m and ε = strain = 12 × 10⁻⁵

So, σ = Yε

Since Y = 2 × 10¹¹ N/m².

Substituting the values of the variables into the equation, we have

σ = Yε

σ = 2 × 10¹¹ N/m² × 12 × 10⁻⁵

σ = 24 × 10⁶ N/m²

Since σ = T/A

T = σA

T = σπd²/4

Substituting the values of the variables into the equation, we have

T = σπd²/4

T = 24 × 10⁶ N/m² × π × (4 × 10⁻³ m)²/4

T = 24 × 10⁶ N/m² × π × 16 × 10⁻⁶ m²/4

T = 24 × 10⁶ N/m² × π × 4 × 10⁻⁶ m²

T = 96 N × π

T = 301.59 N

T ≅ 301.6 N

So, the increase in tension in the steel wire is 301.6 N

The direction of applied force has to be .............. to the distance in order to say work is done​

Answers

Answer:

Parallel

Explanation:

The work done is defined as the force applied on an object and the displacement in the position of the object in the direction of force.

W = F s cos A

where, F is the force, s is the displacement and A is the angle between force and displacement.

When the angle between the force and the displacement is 90 degree, the work done is zero.

To get the maximum work the angle between the force and the displacement is 0 degree.

So, to get the work done by the force the angle between the force and displacement is 0 degree that means the force and displacement is parallel to each other.

a car moves at a speed of 40km/h. it is stopped by applying brake which produce a uniform acceleration of-0.5m/s^2. how much distance will it move before coming to stop ?

Answers

Answer:

Explanation:

We first need to convert the 40 km/h to m/s. Going by the fact that 40 has only 1 significant figure in it, 40 km/h = 10 m/s. The rest of the values are in their proper labels. We will use the equation:

[tex]v^2=v_0^2+2a[/tex]Δx where the final velocity is 0 because the car is coming to a stop at the end; the initial velocity is 10 m/s, the acceleration (or, rather, deceleration) is -.5 m/s/s, and our unknown which is displacement. Filling in:

[tex]0=(10)^2+2(-.5)[/tex]Δx and solving for Δx:

Δx = [tex]\frac{-100}{2(-.5)}[/tex] which ends up being simply that

Δx = 100 m

A 4000 N force acts on an object that initially has a momentum of 400 kg-m/s for 0.9 seconds. What is the final momentum of the system?

Answers

Answer:

4360 Kgm/s

Explanation:

Applying,

Ft = M-M'................. Equation 1

Where F = force, t = time, M = Final momentum, M' = Initial momentum.

make M the subject of the equation

M = Ft+M'............ Equation 2

From the question,

Given: F = 4000 N, t = 0.9 seconds, M' = 400 kg-m/s

Substitute these values into equation 2

M = 4000+(0.9×400)

M = 4000+360

M = 4360 kgm/s

Hence the final momentum is 4360 kgm/s

Angie walked a distance of 90 meters east in 70 seconds. What was her
velocity?
A. 0.78 m/s east
B. 1.3 m/s east
O C. 7 m/s east
D. 9 m/s east

Answers

Answer:

1.3 m/s east

Step-by-step explanation:

90/70 = 1.3

Her velocity is 1.3

can someone pls help me calculate this?

Answers

Answer:

10N is the answerrrerreer

Answer:

f= 100N

Explanation: F=m×(v₀-vf/t)

=0.05ₓ(200-0/0.1)

=0.05ₓ2000

=100N

please mark as brainliest

A jet airplane is in level flight. The mass of the airplane is m=8950 kg. The airplane travels at a constant speed around a circular path of radius R=9.33 mi and makes one revolution every T=0.123 h. Given that the lift force acts perpendicularly upward from the plane defined by the wings, what is the magnitude of the lift force acting on the airplane?

Answers

Answer:

The net force is 91780.8 N.

Explanation:

mass, m = 8950 kg

Radius, R = 9.33 miles = 15015.2 m

Time, T = 0.123 h = 442.8 s

There are two forces acting on the plane.

Horizontal force is the centripetal force and the vertical force is the weight.

[tex]Fx =m R w^2\\\\Fx = m R \frac{4\pi^2}{T^2}\\\\Fx = 8950\times 15015.2\times \frac{4\times 3.14\times 3.14}{442.8\times 442.8}\\\\Fx = 27030.8 N \\\\Fy = m g \\\\ Fy = 8950\times 9.8 \\\\Fy = 87710 N[/tex]

The net force is

[tex]F = \sqrt{Fx^2 + Fy^2}\\\\F = \sqrt {27030.8^2 + 87710^2}\\\\F = 91780.8 N[/tex]

diffusion in physics​

Answers

Answer:

sorry but which class your talking 'bout

20. A semiconductor is a
A) crystalline solid that conducts current under any condition
B) metallic solid that conducts current under any condition
C) metallic solid that conducts current under certain conditions
D) crystalline solid that conducts current under certain conditions

Answers

Answer:

D) crystalline solid that conducts current under certain conditions

Explanation:

A semiconductor is any crystalline solid material whose electrical conductivity is intermediary between that of insulators and conductors. That is, a semiconductor does not conduct like a conductor but does more than an insulator.

Based on this, a semiconductor is said to only conduct electricity under certain conditions as opposed to conductors that do so under any condition. Example of semiconductors are silicon, carbon, antimony, arsenic etc.

Una rueda tiene 4 cm de diámetro y realiza
200 vueltas cada 5 minutos. Calcular:
a. la frecuencia
b. el período
c. la velocidad lineal o tangencial
d. La velocidad angular
e. La aceleración centrípeta.

Answers

Answer:

Una rueda tiene 4 cm de diametro y realiza 200 vueltas cada 4 minutos calcular a frecuencia b el periodo c la velocidad lineal l tangencial

La resistencia de un termómetro de platino es de 6Ω a30°C. Hallar su valor correspondiente a 100°C,sabiendo que el coeficiente de temperatura de resistividad del platino vale 0,00392°C^(-1).

Answers

Respuesta:

7,6 Ω

Explicación:

Paso 1: Información dada

Resistencia a 30 °C (R₀): 6 ΩCoeficiente de temperatura (α): 0,00392 °C⁻¹

Paso 2: Hallar la resistencia (R) a 100 °C

Podemos ver la relación entre la resistencia de un material y la temperatura usando la siguiente ecuación.

R = R₀ (1  + α × ΔT)

R = 6 Ω (1  + 0,00392 °C⁻¹ × (100 °C - 30 °C)) = 7,6 Ω

a. A man of 100 kg mass is standing on the surface of the earth of mass 6 × 1024 kg and
radius 6400km. Calculate the gravitational force between them. [Ans: 977.05 N]

Answers

Answer:

m1=100kg

m2=6×10^24kg

r=6400km

G=6.6×10^-11

F=?

as we know that

F=G m1.m2/r²

F=6.6×10^-11×100×6×10^24/(6400)²

F=6.6×10^-11×6×10^26/4.096×10^7

F=6.6×10^-11×1.465×10^19

F=9.67×10^8N

mention various medium level and higher level human resources related to engineering.

Answers

Answer:

Higher-level human resources related to engineering are those who:

Assist other engineers with solving complex problems. Work with management to keep the project on track. Mentor younger engineers

Medium Level engineers will normally comprise the following:

They are responsible for developing engineering plans and performing calculations with respect to the same.  Project workflow management Engineering Support facilitation Project Reporting Coordination of Team Members

Cheers

The energy required to change the state of a substance was determined to be E(H).
If the mass of the substance was DOUBLED, the value of E(H) will

(A) be halved
(B) be doubled
(C) be quadrupled
(D) remain constant

Answers

Answer:

ccccccccc or bbbbbbb or aaaaaaaa or ddddddd

ANSWER: A
im just guessing

describe how air resistance would affect a falling object ​

Answers

Answer:

With air resistance, acceleration throughout a fall gets less than gravity (g) because air resistance affects the movement of the falling object by slowing it down. How much it slows the object down depends on the surface area of the object and its speed

Explanation:

PLZ MARK AS THE BRAINLIEST

HAVE A GOOD DAY

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What's an area of the earth that suggest that " the Earth is like one giant jigsaw" idea could be true.

Answers

An area of the earth that suggests the earth is one big jigsaw is, the outer surface.

A CROW BAR WITH LENGTH 200 CM IS USED TO LIFT A LOAD OF 600N . IF THE DISTANCE BETWEEN FULCRUM AND LOAD IS 0.75. CALCULATE ; a, effort b, MA c, VR

Answers

Answer:

a. Effort = 960 Newton

b. Mechanical advantage (M.A) = 0.625

c. Velocity ratio (V.R) = 1.67

Explanation:

Given the following data;

Load = 600 NLength of crowbar = 200 cmLength of load arm = 0.75 m

Conversion:

100 cm = 1 m

X cm = 0.75 m

Cross-multiplying, we have;

X = 0.75 * 100 = 75 cm

First of all, we would find the effort arm;

Effort arm = length of crow bar - length of load arm

Effort arm = 200 - 75

Effort arm = 125 cm

Next, we would determine the mechanical advantage (M.A) of the crow bar;

[tex] M.A = \frac {Effort \; arm}{Load \; arm} [/tex]

Substituting the values into the formula, we have;

[tex] M.A = \frac {125}{200} [/tex]

M.A = 0.625

To find the effort of the crow bar;

[tex] M.A = \frac {Load}{Effort} [/tex]

Making "effort" the subject of formula, we have;

[tex] Effort = \frac {Load}{M.A} [/tex]

[tex] Effort = \frac {600}{0.625} [/tex]

Effort = 960 Newton

Lastly, we would determine the velocity ratio (V.R);

[tex] V.R = \frac {length \; of \; effort \; arm}{length \; of \; load \; arm} [/tex]

[tex] V.R = \frac {125}{75} [/tex]

V.R = 1.67

Two children sitting on a see saw such that they can't swing.what is the net torque in this situation ??? Need an appropriate answer

Answers

Answer:

two childrens are sitting on a see saw but can't swing.it means both weight is same (a=b)

Explanation:

hope it will help u please mark me brillient

Answer:

which subject is that question

Why are houses in hot areas painted in white while those in cold areas painted with dull colours

Answers

Answer:

Because white color reflects back the heat coming from the sun while dull colors absorb the heat.

A large atomic bomb produces around 8.00x1015J of energy. How much matter does that bomb turn into energy?

A)2.67x10^79kg

B)2.67x10^7kg

C)7.20x10^32kg

D)0.0889kg

Answers

Answer:

D)0.0889kg

Explanation:

If a large atomic bomb produces around 8.00x10¹⁵J of energy, then from Einstein's energy law i.e E=mc² we can calculate that the amount of matter is  0.0889kg. The correct option is D.

What is Einstein's energy law?

The Einstein Energy Law, often referred to as Einstein's famous equation relates the energy of a particle (E) to its mass (m) and the speed of light (c). The equation is as follows:

E = mc²

This equation shows that energy (E) and mass (m) are equivalent and interchangeable and that a small amount of mass can be converted into a large amount of energy. This is the basis for understanding nuclear reactions and the energy released in processes like nuclear fusion and fission.

Here in the question,

To calculate the mass that is converted into energy in an 8.00x10¹⁵J nuclear reaction, we can rearrange the equation to solve for m:

m = E / c²

where c = 3 x 10⁸ m/s is the speed of light in a vacuum.

Substituting the values, we get:

m = 8.00x10¹⁵ J / (3 x 10⁸ m/s)²

m = 0.0889kg

Therefore, a large atomic bomb that produces around 8.00x10¹⁵ J of energy converts approximately 0.0889kg of matter into energy. This is a very small amount of matter, but because is such a large number, a huge amount of energy can be released from a small amount of matter in a nuclear reaction.

To learn more about Einstein's energy law click:

https://brainly.com/question/2292817

#SPJ2

When the system pressures are lower than the pressure in the refrigerant tank, such as when the system has just been evacuated or if the system is out of refrigerant, refrigerant can be added to both the high and low pressure sides of the system. A. True B. False

Answers

Answer: True

Explanation:

It should be noted that when refrigerant is added in vapor form to the operating refrigeration system, then the addition of the refrigerant should be to the low-pressure side of the refrigeration system.

Furthermore, when system pressures are lower than the pressure in the refrigerant tank as stated in the question, then the refrigerant can be added to both the high and low pressure sides of the system.

Therefore, the correct option is true.

Annie has a soccer ball and a cake ball she kicks each ball with the same Force the soccer ball accelerates at 3 m per second squared and the kickball accelerates at 5 m per second squared use Newton's law to describe why the kickball has a greater acceleration

Answers

Answer: The acceleration will be greater in the kickball than the soccer ball since the kick ball has a smaller mass and provided they are acted upon with equal force magnitude.

Explanation:

We can prove this by substituting with numerical values.

Say the force she kicked both balls with was 30 N. The mass of the soccer ball is 10kg and the mass of the kickball is 6kg.

Applying Newtons Second Law, F = ma

For the soccer ball:

30 = 10a
a = 30/10
a = 3

For the kickball:

30 = 6a
a = 30/6
a = 5

Hence the kickball will travel with a greater acceleration given the same force is acted upon and has a smaller mass than the soccer ball

Hope this helps, brainliest would be appreciated :)

According to Moseley, the properties of elements are a
periodic function of their

Answers

Answer:

According to Henry Moseley, Atomic number is the fundamental property of the elements because elements are made up of atoms . ... So the physical and chemical properties of elements are periodic functions of their atomic number.

Si dejamos caer un objeto desde una gran altura, ¿será que tiene siempre la misma velocidad

Answers

la respuesta es si.

Answer:

asdiieiwihebebwiwo3o2iwjw3

personal and unbiased errors belong to​

Answers

personal to systematic errors

unbiased to random errors

A body having uniform velocity has zero acceleration? give reason​

Answers

Answer:

A body having uniform velocity has zero acceleration because

there is not change in velocity.

1. The hydrogen balloons which are used to collect weather information from the atmosphere is made of plastic and never completely filled. Thus the pressure inside and outside are same. The balloon is filled with 150 litres of hydrogen, the air temperature is 27°C and the atmospheric pressure is 98 kPa. The balloon rises to a height where it radios back that the pressure is 30kPa and the temperature is - 33°C. i. What is the Kelvin temperature equivalent to 27°C and -33°C? (1 mark) ii. What is the volume of hydrogen at this height? (2 marks)​

Answers

Answer:

Answer:- Volume of the balloon is 5.78 L.

Solution:- There are 0.24 moles of hydrogen gas in a balloon at 35 degree C and 1.05 atm pressure. It asks to calculate the volume of the balloon.

This problem is based on ideal gas law equation:

P = 1.05 atm, n = 0.24 mole, T = 35 + 273 = 308 K

R =

V = ?

The equation could be rearranged for the volume as:

Let's plug in the values and do the calculations to get the volume of the balloon:

V = 5.78 L

So, the volume of the gas balloon is 5.78 L.

Which choice shows the correct sequence of features formed by continued wave erosion?

Answers

Answer:

Wave-cut cliff, sea arch, sea stacks

Explanation:

The effect of a wave erosion is made obvious by the structures formed by the wave action.

The high areas of land adjacent to the incoming wave develop the early features or the formation of wave action, which includes the wave-cut cliff

The continuous undercutting of the cliff by the wave results in the formation of the wave cut platform

The effect of the wave further on a cliff, results in the formation of a sea arch and finally a sea stack

Therefore, the correct sequence is the wave-cut cliff, sea arch, sea stacks

use the particle model to explain why the water expands

Answers

Answer:

Take water as an example; the size, shape and chemical composition of the water particles remains the same whether it is solid water (ice) or gaseous water (steam) - but how those particles move and are arranged is different for

a car of mass 500 kg travelling with a speed of 54km/hr is brought to rest over a distance of 40 m. find the acceleration and force applied on brakes​

Answers

Answer:

Explanation:

[tex]a=\frac{v_f-v_0}{t}[/tex] We don't yet need the mass of the car, as we can see by this equation. What we do need is the velocity of the car, the initial velocity, in meters per second, and right now it's in km/hr. Not good. We need to convert. The conversion is as follows:

[tex]54\frac{km}{hr}*\frac{1000m}{1km}*\frac{1hr}{3600s}=15\frac{m}{s}[/tex] Ok, that's good. Now we have everything we need but the time element. If the car traveled a distance of 40 meters at 15 m/s, then we can use the d = rt equation to solve for t, and when we find t we plug it into the acceleration equation:

40 = 15t and

t = 2.7 seconds. The car traveled for 2.7 seconds to go that 40 meters. That's the only reason we were given the displacement. We need it for nothing else but that.

Filling in the acceleration equation now:

[tex]a=\frac{0-15}{2.7}=-5.6\frac{m}{s^2}[/tex] and the negative indicates we are in fact slowing down. That's the answer for the acceleration portion of the problem; now we need the force, F, applied to the brakes.

F = ma where m is mass (we get to use that value now!) and a is -5.6 m/s/s.

F = 500(-5.6) and

F = -2800 N and the negative here means that the force of the brakes is acting against the motion of the car: the brakes are pulling the car "backwards" to stop while the car's motion is forward. The negative indicates the direction the force is being applied.

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The animals believed every word of it. Truth to tell, Jones and all he stood for had almost faded out of their memories. They knew that life nowadays was harsh and bare, that they were often hungry and often cold, and that they were usually working when they were not asleep. But doubtless it had been worse in the old days. They were glad to believe so. Besides, in those days they had been slaves and now they were free, and that made all the difference, as Squealer did not fail to point out.How does this passage demonstrate the use of propaganda? Select two options.It demonstrates repetition because Squealer reminds the animals that they are free at the farm because of the work they are doing.It demonstrates hyperbole because Squealer exaggerates the figures related to positive developments of the farm.It demonstrates bandwagon because Squealer convinces the animals that life is better now than it was before, and everyone agrees because the report says so.It demonstrates plain folks because Squealer explains why the pigs and dogs deserve better food rations than the other animals.It demonstrates glittering generalities because Squealer does not explain the claim that equality in rations would be contrary to the farms ideals. Both the nervous and endocrine systems send electrical and chemical signals for internal communication. Thank you so much thank yall for your help