Answer:
A black hole is a region of spacetime where gravity is so strong that nothing—no particles or even electromagnetic radiation such as light—can escape from it.[1] The theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole.[2][3]
The boundary of the region from which no escape is possible is called the event horizon. Although the event horizon has an enormous effect on the fate and circumstances of an object crossing it, according to general relativity it has no locally detectable features.[4] In many ways, a black hole acts like an ideal black body, as it reflects no light.[5][6] Moreover, quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is on the order of billionths of a kelvin for black holes of stellar mass, making it essentially impossible to observe directly.
Objects whose gravitational fields are too strong for light to escape were first considered in the 18th century by John Michell and Pierre-Simon Laplace.[7] The first modern solution of general relativity that would characterize a black hole was found by Karl Schwarzschild in 1916, although its interpretation as a region of space from which nothing can escape was first published by David Finkelstein in 1958. Black holes were long considered a mathematical curiosity; it was not until the 1960s that theoretical work showed they were a generic prediction of general relativity. The discovery of neutron stars by Jocelyn Bell Burnell in 1967 sparked interest in gravitationally collapsed compact objects as a possible astrophysical reality.
Black holes of stellar mass are expected to form when very massive stars collapse at the end of their life cycle. After a black hole has formed, it can continue to grow by absorbing mass from its surroundings. By absorbing other stars and merging with other black holes, supermassive black holes of millions of solar masses (M☉) may form. There is consensus that supermassive black holes exist in the centers of most galaxies.
The presence of a black hole can be inferred through its interaction with other matter and with electromagnetic radiation such as visible light. Matter that falls onto a black hole can form an external accretion disk heated by friction, forming quasars, some of the brightest objects in the universe. Stars passing too close to a supermassive black hole can be shred into streamers that shine very brightly before being "swallowed."[8] If there are other stars orbiting a black hole, their orbits can be used to determine the black hole's mass and location. Such observations can be used to exclude possible alternatives such as neutron stars. In this way, astronomers have identified numerous stellar black hole candidates in binary systems, and established that the radio source known as Sagittarius A*, at the core of the Milky Way galaxy, contains a supermassive black hole of about 4.3 million solar masses.
On 11 February 2016, the LIGO Scientific Collaboration and the Virgo collaboration announced the first direct detection of gravitational waves, which also represented the first observation of a black hole merger.[9] As of December 2018, eleven gravitational wave events have been observed that originated from ten merging black holes (along with one binary neutron star merger).[10][11] On 10 April 2019, the first direct image of a black hole and its vicinity was published, following observations made by the Event Horizon Telescope in 2017 of the supermassive black hole in Messier 87's galactic centre.[12][13][14]
Blackness of space with black marked as center of donut of orange and red gases
The supermassive black hole at the core of supergiant elliptical galaxy Messier 87, with a mass about 7 billion times that of the Sun,[15] as depicted in the first false-colour image in radio waves released by the Event Horizon Telescope (10 April 2019).[16][12][17][18] Visible are the crescent-shaped emission ring and central shadow,[19] which are gravitationally magnified views of the black hole's photon ring and the photon capture zone of its event horizon. The crescent shape arises from the black hole's rotation and relativistic beaming; the shadow is about 2.6 times the diameter of the event horizon.[12]
Schwarzschild black hole
Simulation of gravitational lensing by a black hole, which distorts the image of a galaxy in the background
Gas cloud being ripped apart by black hole at the centre of the Milky Way (observations from 2006, 2010 and 2013 are shown in blue, green and red, respectively).[20]
the human body station 2
Answer:
...?
Explanation:
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A 2.0 kg block is pulled across a horizontal surface by a 15 N force at a constant velocity.a. What is the net force acting on the block?
Answer:
0
Explanation:
the block is being pulled at a constant velocity meaning it has no acceleration. the rule is fnet=mass x acceleration so if theres no acceleration there is no force net!
A block of mass 2 kg is pulled across a surface with a force of 15 N then the net force acting on the block is 0.
What is Force?A force is an effect that can alter an object's motion according to physics. A force might cause an object has mass to accelerate when it changes its velocity, for, us when it moves away from rest. An obvious way to describe force is in terms of push or pull. A force is a vector quantity since it has equal magnitude and direction. It is calculated using the newton SI unit (N). Force is denoted by the letter F.
The net force exerted by an object was equal to the speed at which its velocity varies over time, according to Newton's second law in its original formulation.
The block has no acceleration because it is being pushed at a constant speed. If there is no acceleration, there is no force net because the formula is net force =mass × acceleration.
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What are the characteristics of a blackbody radiator? Give an example.
Answer:
A blackbody, or Planckian radiator, is a cavity within a heated material from which heat cannot escape. No matter what the material, the walls of the cavity exhibit a characteristic spectral emission, which is a function of its temperature.
Example:
Emission from a blackbody is temperature dependent and at high temperature, a blackbody will emit a spectrum of photon energies that span the visible range, and therefore it will appear white. The Sun is an example of a high-temperature blackbody.
I am giving 18 points. Please try and don’t just do it for the points.
They won’t let me shown the very last picture, it looks like the normal L shape that is in every picture, and just one straight line. L—
Like that.
Which of the following graphs below represents the motion of an object at variable speeds? (3 points)
Distance
(miles)
Time
(hours)
Distance
(miles)
Time
(hours)
Answer:Distance.
Explanation:
Given the impulse acting on an object and the impact time which equation can be used to calculate the force applied to an object
Answer is D
Ndmdjdndbdjdkskd
The impulse acting on an object and the impact time, the equation F= I / Δt can be used to calculate the force applied to an object, therefore the correct answer is D.
What is impulse?The product of the average applied force and the time for which it is exerted is known as an impulse.
the mathematical relation for impulse is
Impulse = F * Δt
where F represents the force applied and Δt represents the time for which the force is applied
Thus, the correct equation that can be used to calculate the force applied to an object is F = I /Δt and the correct option is D.
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Why is a protective apron or lab coat important to use when working with acids?
Acids conduct electricity and contact could cause a shock.
Acids react with lipids and can cause damage to skin tissue.
Acids break down fabrics and can cause burns if the acids are strong.
Acids have a slippery feel and could result in a fall.
Answer:
Acids break down fabrics and can cause burns if the acids are strong.
Explanation:
A protective apron or lab coat is important when working with acids because acids break down fabrics and can cause burns if the acids are strong.
An acid is a substance that interacts with water to produce excess hydroxonium ions in an aqueous solution. A strong acid ionizes completely in solution. When they come in contact with a fabric, they break them down violently. So, if they come in contact with the skin, it causes a violent break down of body tissues. The apron acts a protective layer.Answer:
C
Explanation:
I got it right
Ozone gas in the atmosphere protects living things on Earth from some of the Sun's harmful
rays. The chemical formula for ozone is 03.
Complete the statement.
Ozone is
an elementary substance
or is it an compound
Answer:
Ozone is a compound.
Explanation:
Elements are simple atoms that can merge or combine to produce a bigger molecule called a compound. They can not be splitted into smaller atoms. Examples are: hydrogen, carbon, etc.
A compound is formed as a result of the combination of two or more elements. They can be splitted into elements. Examples are: ammonium, water, carbon dioxide etc.
Ozone ([tex]O_{3}[/tex]) is a less stable allotrope of oxygen which is made up of three atoms of oxygen. Therefore, it is a compound.
Which of the following is not a shared similarity between warm-up and cool-
down routines?
A. Stretches performed can be the same.
B. Consist of a modified version of the exercise performed, such as a
slow jog before or after a strenuous run.
C. Restore muscles to their resting length.
D. Help prevent injury.
C. Restore muscles to their resting length
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A bungee jumper starts with 1000 J in their GPE store. After they jump they fall and are brought to a stop with the bungee cord. With the cord fully stretched what is the energy in the EPE store?
Answer:
energy is equal to 1000 J
Explanation:
When the jumper is in the tent, he has a given height, this height gives him a gravitational potential energy, which forms his initial mechanical energy of 1000 J. After jumping, this energy is converted into elastic energy of the rope plus a remainder of potential energy gravitational, it does not reach the ground, but as the friction is negligible the total mechanical energy is conserved, therefore its energy is equal to 1000 J
This is a case of energy transformation, but the total value of mechanical energy does not change
if an object with a mass of 248kg is lifted 76 meters in 18 seconds, how much power is used?
Explanation:
power = 1/2 mass × velocity^2 >>1
velocity = distance / time = 76 /18 = 4.2m
then power = 1/2 × 276 × (4.2)^2 = 138 × 17.64 = 2,434.3 jules.
Un consumator electric conectat la o tensiune de 220V are rezistenta electrica R=100ohmi Ce putere electrica are consumatorul? 1 point 484W 220W 440W
TRUE OR FALSE Light can travel through materials that you cannot see through, like wood or aluminum foil.
Answer: TRUE
Explanation:
(Example): If there was lightening outside, the lightening (light) could travel through a tree (that you cannot see through).
The statement Light can travel through materials that you cannot see through, like wood or aluminum foil, is True.
What is light?Electromagnetic radiation that the human eye can detect as light. The wavelengths of electromagnetic radiation cover a very broad spectrum. Information about space and time is transmitted by light. This characteristic serves as the foundation for the study of optics, optical communications, and a wide range of other related, both established and developing technologies.
Lasers, holography, and fiber-optic communication systems are examples of technologies that use light manipulation. The electromagnetic spectrum, which includes all forms of light, propagates in a vacuum at the same speeds, c. only a small portion of which is visible to humans. And it is unquestionably possible for non-visible light to pass through wood, including radio waves, x-rays, and gamma-energy photons.
Therefore, the statement Light can travel through materials that you cannot see through, like wood or aluminum foil, is True.
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Which of the following is an example of kinetic energy?
athlete running in a race
battery charging in a garage
apple hanging from a tree
water boiling on a stove
Answer:
A. Athlete running in a race
Explanation:
Kinetic energy haves something to do with movement
How can shorter string produce more fundamental frequency in two string of different length?
Answer:
Shorter string produces more frequency in two different strings because the equation for frequency is velocity/wavelength , this means that a shorter string creates a shorter wavelength which essentially increases the total frequency produced
Sam is moving house and is carrying a 300N box of books up a flight of steps 5m high, it takes her 30 seconds. Gary follows her carrying a bag of clothes doing 1000 J of work; it only takes him 25 seconds. Who provides the biggest power? Show your working.
Answer: Sam provides the biggest power
Explanation: Power is defined, in Physics, as the rate of work done. Work is energy transferred to an object due to the force causing the displacement of the object.
So, to determine Power:
For Sam:
P = [tex]\frac{work}{time}[/tex]
[tex]P=\frac{F.d}{t}[/tex]
[tex]P=\frac{300.5}{30}[/tex]
P = 50 Watts
The unit for Power is [P] = J/s = Watt
For Gary:
P = [tex]\frac{work}{time}[/tex]
[tex]P=\frac{1000}{25}[/tex]
P = 40 Watts
Comparing power of Sam and Gary, we can conclude that Sam provides the biggest power of 50 Watts.
Evelyn is making a model of Earth to show how the physical layers correspond to the compositional layers. Which of the following should Evelyn show in her model?
The physical layers exactly match the compositional layers.-A
The crust is the only compositional layer not included in the physical layers. -B
The physical layers of the inner core and outer core form a single compositional layer. -C
The physical layer of the asthenosphere includes the compositional layer of the crust.-D
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Answer:
B
Explanation:
When materials absorb heat, the kinetic energy of the particles _________?
a. increases
b. decreases
c. remains the same
Answer:
A
Explanation:
The atoms started to get "overly excited" and started to move faster than they usually do. When this happens, energy is released in the form of heat, light or etc. Because of this, kinetic energy increases and atoms colliding with each other happens more often.
Which of the following formulas is the correct equation for the law of Universal gravitation?
Answer:
F = GMm / r²
from Newton's law of gravitational attraction
Which list includes the phase changes that require a loss of energy (heat)?
a. sublimation and deposition
b. condensation, freezing and deposition
c. freezing and melting
d. melting, vaporization and sublimation
Answer:
b
Explanation:
because if you freeze somthing you do not gain heat you loss heat.
A sound wave traveling through dry air has a frequency of 16 Hz, a
wavelength of 22 m, and a speed of 350 m/s. When the sound wave passes
through a cloud of methane, its wavelength changes to 28 m, while its
frequency remains the same. What is its new speed? (The equation for the
speed of a wave is v= f x.)
A. 350 m/s
B. 9,800 m/s
C. 450 m/s
D. 13 m/s
Answer:
C. 450
it should be right
The new speed of sound wave is 450 m/s. Hence, option (C) is correct.
What is sound wave?A sound wave is the pattern of disruption brought on by the movement of energy moving through a medium as it propagates away from the source of the sound (such as air, water, or any other liquid or solid matter).
Pressure waves are produced when an object vibrates, such as a ringing phone, and these waves are known as sound waves.
Frequency of sound wave is = 16 Hz.
Wavelength of the sound wave is = 28 m.
Hence, new speed of sound wave is = 16 × 28 meter/second
= 448 meter/second
=450 meter/second. (approx.)
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What is the Sl unit for momentum?
O kg• m
O kg
O kg• m
O kg
2
m
Explanation:
The S. I. unit of momentum is Kg. m/sechope it helps you
please help me answer these
The box is applying 22 N of force on the table, but the box is not moving 22 N If there is a downward force of 22 N, why is the box not moving downward?
Answer:
A reaction force
Explanation:
The box is not moving downward because the table is applying an equal and opposite amount of force on the box.
This is the premise of Newton's third law of motion which states that "action and reaction are equal and opposite".
The action force impacted by the downward pull on the table is being cancelled out by the upward force of the table.
The net force in the vertical direction will therefore be 0N This way, the box does not move downward.The distance that the pointer of a galvanometer moves depends on the amount of magnetism in the loops of the armature.
Please select the best answer from the choices provided
T
F
• How can you find the temperature in Fahrenheit when its given in the
Celsius scale?
I
Answer:
there are conversion scales used for doing that
to convert Celsius to Fahrenheit we use the formula,
T(°F) = T(°C) × 9/5 + 32
and to convert Fahrenheit to Celsius we use,
T(°F) = T(°C) × 5/9 + 32
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Explanation:
What is used to turn the pointer of a galvanometer?
a.
a crank
b.
an electric current
c.
a bar magnet
d.
a battery
Answer:
b. an electric current is used to turn the pointer of a galvanometer
Explanation:
well , galvanometer is an important device which is used to detect an electric current through a conductor or circuit.
something special about it is that it can detect very minute current too
Answer:
b
Explanation:
how would a position-time function look like for linearly increasing negative velocity regions?
Answer:
Hmmm
Explanation:
Here what I know... If a function gives the position of something as a function of time, the first derivative gives its velocity, and the second derivative gives its acceleration. So, you differentiate position to get velocity, and you differentiate velocity to get acceleration. where t is in seconds and H(t) is in inches.
Does this help?
Name two sub-kingdoms of plant kingdoms
Answer:
⭐. cryptogams ( non-flowering & non-seed bearing)
⭐. phanerogams ( flowering & seed bearing)
What is the relationship among
gravitational force, mass, and the distance
between two objects, as described by
Newton's law of gravitation?