The sound level at a distance of 3.00m from a source is 120dB at [tex]9.48*10^{5}\;m[/tex] distance is the sound level 10.0 dB
What do you mean by sound level?The RMS (root-mean-squared) of the sound pressure measured and averaged over a given length of time is the sound level in decibels. When measured by contemporary integrating sound level meters, measurements are often A-weighted to coincide with the human reaction; see the time-average sound level definition for more information. These measurements are now commonly referred to as the LA eq. Sound pressure is defined as having a sound level when it is compared to a reference sound pressure of 20 Pa using a standard exponential time weighting and a standard frequency weighting. The ratio of the base ten logarithms to the ratio of the sound level in decibels.
(Lw) = 10·log (W/Wo) dB
Given:
Sound level, [tex]Beta = 120\;dB[/tex]
Sound level, [tex]Beta_{a} = 10\;dB[/tex]
r = 3 m
[tex]P = 4\pi r^{2}I\;\;\;\;------equation(1)[/tex]
We know that,
[tex]\beta = 10 \times log(\frac{I}{I_{o} } )[/tex]
Where, [tex]I_{o}=1 \times 10^{-12}\;W/m^{2}[/tex]
Substitute the known value in the sound level equation,
[tex]10 = 10 \times log(\frac{I_{a} }{1 \times 10^{-12} } )[/tex]
[tex]1 = log(\frac{I_{a}}{1 \times 10^{-12} } )[/tex]
[tex]10= \frac{I_{a}}{1 \times 10^{-12} }[/tex]
[tex]I_{a}= 10 \times 1 \times 10^{-12}[/tex]
[tex]I_{a}=1 \times 10^{-11}\;W/m^{2}[/tex]
[tex]P = 4\pi r_{a} ^{2}x_{123} I_{a} \;\;\;\;------equation(2)[/tex]
equation(1) and (2) are equal,
[tex]4\pi r^{2}I = 4\pi r_{a} ^{2}x_{123} I_{a}[/tex]
Simplify the above equation,
[tex]r_{a} = \sqrt{(\frac{I}{I_{a} } )}\;\;r[/tex]
Substitute the known values in the above equation,
[tex]r_{a} = \sqrt{(\frac{1 \times 10^{-12} }{1 \times 10^{-11} } )}\;\times 3[/tex]
By solving the above equation, We get,
[tex]r_{a} = 9.48 \times 10^{5}\;m[/tex]
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All stars are born with the same basic composition, yet stars can look quite different from one another. Which two factors primarily determine the characteristics of a star?.
Answer:
Mass and Its stage of life
Explanation:
All stars are born with the same basic composition, yet stars can look quite different from one another. Its mass and its stage of life.
Which of the following situations has more kinetic energy than potential energy?
Answer: I think its C
Explanation:
Answer:
a rolling bowling ball
Explanation:
a rock at the edge of a cliff, an archer’s bow that is drawn back, a rolling bowling ball, a car waiting at a red light
moving is kinetic energy a rolling bowling ball is the only one with movement
All BUT ONE statement provides evidence supporting plate tectonics, through data collected at the sites of sea floor spreading. That is
All BUT ONE statement provides evidence supporting plate tectonics, through data collected at the sites of sea floor spreading. That is... paleomagnetic reversals in specific areas of the sea floor.
Paleomagnetism, often known as palaeomagnetism, is indeed the study of magnetic field records found in rocks, silt, and other prehistoric materials. When magnetic minerals occur in rocks, they may record the strength and direction of the magnetic field.
Hence, paleomagnetic reversals in specific areas of the sea floor, Paleomagnetism is related to mid-ocean ridges since it is among the most trustworthy techniques for scientists to make a magnetic history of the evolution of the Earth's magnetic field. New rock is continuously formed at an ocean's bottom rift as a result of seafloor spreading.
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Heat transfers through Earth's systems in different ways. In which atmospheric action can we see evidence of conduction? Cold air pushes warm air upward, creating a current. Cold air pushes warm air upward, creating a current. The surface of the Earth heats the air that contacts it. The surface of the Earth heats the air that contacts it. Radiation from the Sun heats the surface of the Earth. Radiation from the Sun heats the surface of the Earth. Air increases in density and sinks back towards the Earth.
Answer:
B. The surface of the Earth heats the air that contacts it.
Explanation:
Conduction is a mode of heat transfer in which energy is transferred from a hot molecule to the neighboring molecules due to contact. Thus, heat energy is transferred from one molecule to another in the process.
Therefore, the air that comes in contact with the surface of the earth heats up by conduction. Since the surface of the earth is heated up due to the radiation from the Sun.
Answer: B.
Explanation: I took the test. Also, after my diagnostic I just wanted to see if my answers were correct lol.
PLEASE HELP ME
Imagine a metal cooking pan with a wooden handle is placed into a 200 °c oven.
Which material (wood or metal) would reach thermal equilibrium most rapidly? Why?
Answer:
The pan because it is directly on there to absorb heat while the handle is there more towards the end and will have heat reaching the start of the handle while the metal is already hot
A) a 70 kg runner begins his slide into third base moving at a speed of 4 m/s. How much work does friction do to slow him down as he slides into third base?
B) If the runner slides for 2 m, what is the force of friction between the player and the ground?
Answer: I don’t know the answer to this but just do what i do look up the question I’m sure someone has answered this hope it helps❤️
Explanation:
GIVING BRAINLIEST
In addition to having a blue color, what other characteristic do Neptune and Uranus share?
no rings
27 moons
no axis tilt
cold temperatures
Answer:
Cold temps. . .
Explanation:
Hope it helps!
A car starts from rest and accelerates at 4 m/s2 until it reaches 36 m/s. How far did it travel in this time?
The distance of a car that starts from rest and accelerates at 4 m/s² until it reaches 36 m/s is 162m.
How to calculate distance?The distance moved by a body can be calculated using the following formula:
S = ut + ½at²
Where;
S = distanceu = initial velocityt = timea = accelerationHowever, the time taken for the car to complete the acceleration can be calculated as follows:
4 = 36/t
t = 9seconds
S = 0 × t + ½ × 4 × 9²
S = 0 + 162
S = 162m
Therefore, the distance of a car that starts from rest and accelerates at 4 m/s² until it reaches 36 m/s is 162m.
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A uniformly charged, straight filament 7.00m in length has a total positive charge of 2.00μC. An uncharged card-board cylinder 2.00cm in length and 10.0cm in radius surrounds the filament at its center, with the filament as the axis of the cylinder. Using reasonable approximations, find (a) the electric field at the surface of the cylinder
The electric field at the surface of the cylinder is 51428V/m
Given data:
• The length of the charge is l= 7m.
• The charge is q = 2μC..
• The radius the cylinder is r = 10 cm
Since the filament length is so large as compared to the cylinder length that the infinite line of charge can be assumed.
The expression to calculate the electric field is given as,
E=2kλ/r
Here, λ is the linear charge density.
Substitute the values in the above equation,
E = (2×9×109N⋅m^2/C^2×2×10^−6C)/0.1m×7m
E = 51428N/C×(V/m)/(N/C)
=51428V/m
An electric charge is the property of matter where it has more or fewer electrons than protons in its atoms. Electrons carry a negative charge and protons carry a positive charge. Matter is positively charged if it contains more protons than electrons, and negatively charged if it contains more electrons than protons.
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Using the "Rube Goldberg" machine image below, identify the correct simple machine used in this complex machine.
Answer:
c is the correct answer
Explanation:
A Rube Goldberg Machine is “a comically involved, complicated invention, laboriously contrived to preform a simple operation.” 2. What are the 6 Simple Machines? A. The 6 Simple Machines are: wedge, screw, lever, wheel and axel, inclined plane and pulley
Answer: it’s actually A
Explanation:
Anything sharp like a knife, is a wedge so the hook thingy is a wedge
What is the main difference between primary and secondary succession?
A The climax of primary succession is pine forest
B Primary succession begins with bare rocks
C Secondary succession begins with mossed and lichens
D Secondary succession include frequent fires
Answer:
b
Explanation:
"Consiousness is everything. It is the learning instrument that takes effort. The benefits are extreme. When you change your consciousness you change your world, and when you change your world, you change the world. It's as simple as that and it's profound." What does this mean in 1 paragraph?
"Consciousness is everything. Consciousness and "conscious" are catch-all terms that refer to a wide range of mental events. Both have a variety of connotations, and the word "conscious" is used to describe both specific mental states and processes (state consciousness) as well as entire creatures (creature consciousness).
Your distinctive awareness of your own thoughts, memories, emotions, sensations, and surrounds is what is known as consciousness. Being aware of oneself and one's surroundings is the essence of consciousness.
This awareness is personal to you and subjective. It is a sign that something is a part of your consciousness if you can verbalize what you are experiencing.
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Which of the following is an example of a dry lubricant? oil grease graphite petroleum
ANSWER ASAP WILL GIVE BRAINLIEST!
Answer:
Dry lubricants or solid lubricants are materials that, despite being in the solid phase, are able to reduce friction between two surfaces sliding against each other without the need for a liquid oil medium.
Explanation:
Answer:
Your answer is graphite :) Have a nice day
Explanation:
Need help quick!!!!
When trying make an object accelerate, what kind of Net force is required?
A. Balanced Force
B. Unbalanced Force
C. Force of Friction
D. Normal Force
Kiana is wearing a black shirt and shiny necklace. While she is outside at recess her shirt absorbs the light waves and gets very hot in the sun, but her necklace reflects the light waves and small circles of light are seen around the yard. What explains why the light waves behaved differently on her shirt than they did on her necklace?
Answer:
Black bodies are good absorber of light waves from the sun, while shining surfaces are good reflector of the light waves.
Explanation:
Generally, a black surface or material tends to absorb light waves while under the sun, while a shiny surface is a good reflector of the waves. This is because the black material is a good absorber, and also a good emitter.
The shiny necklace can only absorb little light waves from the sun, thus it reflects most of the light waves. The reflection is the reason for the small circles of light seen around the yard.
However, when in a cool environment the black shirt would cools faster (good emitter) than the shiny necklace.
Why should you care
about air masses?
Explanation:
because
1.Extremely warm masses can lead to heat waves
2.Extremely cold air masses can be just as deadly and costly
3.The"clashing "of different air masses can produce regions of severe weather
Which of the following do you NOT need a college education for?
personal trainer
physical therapist
nutritionist
teacher
The type of profession that does not need a college education is personal trainer.
Which profession does not need a college education?Personal trainer is the type of profession that does not need a college education because the personal trainer is not related to any educational subject. This profession can be learned from a trainer not from the teacher in the school or college. Personal trainer is responsible for maintaining the strengths and remove the weaknesses through creating workout plans. It provides physical and mental guidance and also monitor progress of their customer on a regular basis..
So we can conclude that the type of profession that does not need a college education is personal trainer.
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Plz answer all 5 of the questions i will give brainlyest
1.What is force?
2.Relate force and motion.
3.What forces control the motion of everyday objects?
4.Identify and define the SI unit for force.
5.Draw a diagram to represent a foot kicking a resting soccer ball. Use arrows to represent the force applied to the ball and to show how the ball moves after it is kicked.
Answer:
1)force:- force is an external affert by any body on an object.
2) force and motion are related to each other. force helps to create motion in any object.
3) frictional force
4) Newton
Glands in the body send out chemical messages through hormones to control growth, development, and metabolism. The system that helps regulate the body to maintain homeostasis is the-
Answer:
The nervous and endocrine systems exert the ultimate control over homeostasis because they coordinate the functions of the body's systems.
Explanation:
What is the impact of age on flexibility? A. Younger people tend to develop flexibility more slowly. B. Younger people tend to be more flexible. C. Older people tend to be more flexible. D. Older people cannot maintain their flexibility.
Answer:
the answer is b
Explanation:
Calculate the force between two objects that have masses of 70 kilograms and 2,000 Kilograms separated by a distance of 1m
Answer:
The gravitational force between two objects = F = 9.3 x 10⁻⁶ N
Explanation:
Given
m₁ = 70 kg
m₂ = 2000 kg
distance r = 1 m
Thus, the gravitational force between two objects = F = Gm₁m₂ / r²
as
Gravitation constant = G = 6.67430×10⁻¹¹ N⋅m²/kg²
Thus, putting the values
F = Gm₁m₂ / r²
= (6.67430×10⁻¹¹ × 70 × 2000) / 1²
= 9.3 x 10⁻⁶ N
Thus, the gravitational force between two objects = F = 9.3 x 10⁻⁶ N
a vertical spring oscillates with a frequency of 3.0 hz when a 0.60 kg mass is hung from it. determine the frequency when only a 0.38 kg mass hangs from it.
By angular speed, the frequency is 2.39 Hz.
We need to know about the angular speed of harmonic oscillation. the angular speed can be determined as
ω² = k / m
where ω is angular speed, k is spring constant, and m is the mass.
The angular speed can be calculated by
ω = 2πf
Hence,
ω² = k / m
(2πf)² = k / m
k = (2πf)² / m
where f is frequency.
From the question above, we know that:
m1 = 0.6 kg
f1 = 3 Hz
m2 = 0.38 kg
The spring is same, hence the spring constant is the same
k1 = k2
(2πf1)² / m1 = (2πf2)² / m2
f1² / m1 = f2² / m2
3² / 0.6 = f2² / 0.38
f2² = 5.7
f2 = 2.39 Hz
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To what extent do covalent compounds conduct electricity?
O always
O usually
O rarely
O never
Answer:
never....(D)
Explanation:
hope this helps, the person above me is also correct
Covalent compounds never conduct electricity as we know that these compounds are formed by the sharing of electrons where free electrons are unavailable for the flow of the electric current.
Therefore the correct answer is option D.
What is a covalent bond?Covalent bonds are formed between two atoms, whether they are similar or different when they share an extra electron.
The transport of electrons produces the ionic bond.
Intermolecular compounds are known to never carry electricity because they are created by shared electrons, which prevents free electrons from being available for the transmission of an electric current.
Option D is the right response as a result.
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A machine does 500 j of work in 20 sec. What is the power of this machine?
Explanation:
P=W/t
P=500/20
P=25 W
The boat moves forward due to A. a forward thrust from the propeller that is greater than the backward force of the water current. B. a forward thrust from the propeller that is equal to the backward force of the water current. C. a backward thrust from the propeller against the water that is greater than the force of gravity. D. a backward thrust from the propeller against the water that is less than the force of gravity.
Answer:
(B). a forward thrust from the propeller that is equal to the backward force of the water current.
Explanation:
A boat generates thrust when the propellers are turned to accelerate water forward. According to Newton's third law, the resulting thrust pushes the boat in the opposite direction (i.e. backward direction) which is equal in magnitude.
So, the boat moves forward due to a forward thrust from the propeller that is equal to the backward force of the water current.
Hence. option (B) is correct.
50 POINTS & RLLY EASY
Which planet has the features that best describe Mars?
Select one:
A.
-has a lower density than liquid water
- circled by many rings, which are made of light and dust that reflect light easily
- second largest planet in the solar system made of gas and rock
b. has landforms made by flowing liquid water
- has many huge on its surface
- gets its red color from iron oxide present in soil and rocks on surface
- reflects light from sun
c.
- largest and most massive planet in the solar system
-has a huge permanent storm that looks like a red spot in images
- has at least 61 moons orbiting it, some of which are very large
- located closer to the sun than Kuiper Belt
d.
- methane in the atmosphere gives planet a blue-green color
- poles are oriented almost parallel to the planet's orbit
- poles experience constant daylight or darkness for 48 years at a time
- located in our solar system
Answer:
b. has landforms made by flowing liquid water
- has many huge on its surface
- gets its red color from iron oxide present in soil and rocks on surface
- reflects light from sun
Explanation:
If an equation is already balanced, how would you express that in an answer?
A. Write 'balanced as written.'
B. Add a tick next to it.
C. Do not write anything next to it.
Answer:
C. Do not write anything next to it.
Explanation:
If an equation is already balanced there is no need to provide information of that.
the magnitudes of 2 vectors a and b are 12 units and 8 units respectively. what are the largest and smallest possible values for the magnitude of the resultant vector r
When vector A is oriented in the same direction as vector B, the resultant's greatest magnitude is A + B = 12 + 8 = 20 units. When vector A is oriented in the direction opposite to vector B, the resultant vector has its least magnitude, A - B = 12 - 8 = 4 units.
What is a resultant vector?A vector that produces the aggregate impact of all other vectors is known as a resultant vector. The resultant vector is what we get when we combine two or more vectors. The head-to-tail convention, which is defined as "joining the tail of the first vector with the head of the second vector to give another vector whose head is joined with the head of the second vector and tail of the first vector," can be used to geometrically add vectors by drawing them on a common scale.
Any number of vectors can be added by extending the procedures for obtaining a vector's resultant or adding more than two vectors.
R=A+B+C---
Assume there are three vectors: A, B, and C. These vectors must be drawn in accordance with the head-to-tail rule so that the heads of each vector line up. As a result, the resultant vector is as follows:
R=A+B+C
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Proxima Centauri and the Sun are both main-sequence stars, but Proxima Centauri is a red dwarf and the Sun is a yellow dwarf. Based on the information you charted, compare the characteristics of red dwarf stars and yellow dwarf stars.
Answer:
Yellow dwarfs are small, main sequence stars. The Sun is a yellow dwarf. A red dwarf is a small, cool, very faint, main sequence star whose surface temperature is under about 4,000 K. Red dwarfs are the most common type of star. Proxima Centauri is a red dwarf.
Explanation:
Answer:
Red dwarfs are low-mass main-sequence stars. Yellow dwarfs are main-sequence (dwarf) stars with masses comparable to that of the Sun.
Explanation:
Lab report 1.04 hypothesis
Answer:a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.
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