Answer:
a. 90 dB
b. 80 dB
Explanation:
The given parameter of the sound is as follows;
The level to which the headphones are tuned = All the way up
The intensity of the sound of the headphones when tuned all the way up = 100 dB
a. The relationship between level change in loudness, ΔL, and the ratio of loudness, 'x', is presented as follows;
ΔL = 10·log₂(x) ≈ 33.22·log(x)
Therefore, for a sound to be half as loud, we have x = 1/2, therefore;
ΔL = 10·log₂(1/2) = 10·log₂(2⁻¹) = -10 ≈ 33.22·log(1/2)
The change in the intensity level for a sound half as loud, ΔL = -10 dB
Given that the sound was initially at 100 dB, the new level for a sound half as loud = 100 dB + ΔL = 100 dB - 10 dB = 90 dB
The decibel level the music must be set for a sound half as loud = 90 dB
b. In order for the sound to be 1/4 as loud, we have;
ΔL = 10·log₂(1/4) = 10·log₂(2⁻²) = -20
Therefore, the change in the level of the sound intensity level, ΔL by -20 dB will given a sound that is 1/4 as loud
The initial intensity level = 100 dB
The intensity level for a sound 1/4 as loud = 100 dB - 20 dB = 80 dB
If a book has a weight of 23.3 N on earth, what is its mass
Answer:
2.38 kg
Explanation:
by definition, weight in physics is the force of gravity (Fg)
Fg = mass x gravity or mg
gravity is 9.8 m/s^2
N = kg m/s^2
Fg = mg
23.3 kg m/s^2 = 9.8 m/s^2 x m
23.3 kg m/s^2 / 9.8 m/s^2 = m >>> m/s^2 cancel out
23.3/9.8 = 2.37755 kg
m = 2.38 kg
Which device uses electricity to produce a rotational motion? A computer C magnet B generator D motor
Answer:
B generator
Explanation:
What would make oppositely charged objects attract each other more? increasing the positive charge of the positively charged object and increasing the negative charge of the negatively charged object decreasing the positive charge of the positively charged object and decreasing the negative charge of the negatively charged object increasing the distance between the positively charged object and the negatively charged object maintaining the distance between the positively charged object and the negatively charged object
Answer:
A.
Explanation:
I did the test :D
which feature is used to classify galaxies
age
color
shape
size
Answer:Shape
I took the quiz
Answer:shape
Explanation:
I took the quiz
Which of the following
statements is correct?
A. Matter flows one way, but energy cycles in an
ecosystem.
B. Matter cycles in an ecosystem, but energy
flows into, and eventually exits, an ecosystem.
C. Matter and energy can flow and cycle in an
ecosystem, depending on the temperature,
D. Neither matter nor energy cycle in an
ecosystem
The correct statement is B. Matter cycles in an ecosystem, but energy flows into, and eventually exits, an ecosystem.
What is ecosystem?Ecosystem is a community of living organisms interacting with each other and their physical environment. It includes plants, animals, microorganisms, soil, water, and other resources, and the chemical and energy exchanges between them.
This is because energy enters an ecosystem through sunlight and is transformed through the process of photosynthesis by producers, like plants, into chemical energy. This energy is then passed on to consumers, like humans, through a food chain. Eventually, energy exits the ecosystem in the form of heat, which is released into the environment. On the other hand, matter cycles within an ecosystem through a process called the biogeochemical cycle. Nutrients, like carbon and nitrogen, enter the environment from different sources and are taken up by producers and then passed on to consumers. The matter is then returned to the environment as waste, which is then taken up by producers again.
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Which of the following BEST describes what occurs in a fusion reaction?
A.
Two low mass nuclei are joined to form one nucleus.
B.
A single nucleus divides into two or more nuclei and gives off energy.
C.
Electrons are shared between the nuclei.
D.
A chemical reaction occurs between the nuclei.
Answer:
Two mass nuclei are joined to form one nucleus
Explanation:
As the name implies "fusion", it is the joining of lighter nucleus to form a heavier nucleus to produce energy
Some liquid is poured into a burette so that it reads 14cm³.50 drops were run each of volume 0.1cm³ What is the volume of the 50 drops. (4marks)
Answer:
V = 5 cm³
Explanation:
In this exercise the volume (Vo = 0.1 cm³) of each drop is indicated, requesting the volume of 50 drops
V = V₀ #_drops
V = 0.1 50
V = 5 cm³
Answer:
[tex]V_{50}=5cm^3[/tex]
Explanation:
From the question we are told that:
Volume of liquid in burette [tex]V_b=14cm^3[/tex]
Volume of drop of liquid [tex]V_d=0.1cm^3[/tex]
Number of drops [tex]n=50[/tex]
Generally the equation for volume of 50 drops V_{50} is mathematically given by
[tex]V_{50}=V_d*n[/tex]
[tex]V_{50}=0.1*50[/tex]
[tex]V_{50}=5cm^3[/tex]
Therefore the volume of the 50 drops
[tex]V_{50}=5cm^3[/tex]
25. Suppose there is no unbalanced force acting on a moving object. How will
the object's motion continue?
A. The speed of the object will decrease.
B. The speed of the object will increase.
C. The speed of the object will remain the same.
D. The direction of the object's velocity will change.
Answer:
C
Explanation:
Grammar is probably one of the most important components of the sciences besides math.
no unbalanced forces means that there is no force left over that cause an acceleration. All the forces are balanced.
So the Speed will not decrease. Not A.
The speed will not increase. Not B
The direction will not be affected. Not D
The answer is C
why are dams have broader walls at the bottom?
If you are 1 m above the surface of the earth, and then you jump to 2 m above the surface of the earth.
The force of gravity between you and the earth will be:
a.) About 4
b.) About 12
c.) About the same
Answer:
b
Explanation:
I am pushing on a large box with 200N of force. Clint is pushing on the box with 200N of force in the opposite direction. Why won't the box move?
Tom used 75 N of force to push a box 3 meters across the floor. How much work did he do?
0.12 J
25 J
1
78J
225 J
Answer:
It must be 225 J.
Explanation:
According to
Work done = Force × distance travelled
= 75 × 3
= 225 J
This answer is taken so since no angles are stated in the question.
Which wave has the lowest amplitude?
Wave D has the lowest amplitude. The highest point of a wave is called amplitude.
What is amplitude?The distance between from the crest of a wave to the next crest is known as the amplitude. It is denoted by a.
The standard equation for the SHM is found as;
[tex]\rm y = asin \omega t[/tex]
Where, a represent the amplitude of the wave.
In the wave D it is observed that the distance from center axis to the highest point of the wave is smallest. Hence, wave D has the lowest amplitude.
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Answer:
To summarize what the expert answer said, it's the last box.
Explanation:
Help meeee help plsssss
Answer:
3a. 240 C
3b. 3666.67 A
Explanation:
3a. Determination of the charge.
Current (I) = 2 A
Time (t) = 120 s
Charge (Q) =?
The charge, current and time are related by the following equation:
Charge (Q) = current (I) × time (t)
Q = It
With the above formula, we can obtain the charge as follow:
Current (I) = 2 A
Time (t) = 120 s
Charge (Q) =?
Q = It
Q = 2 × 120
Q = 240 C
Thus, the charge is 240 C
3b. Determination of the current
We'll begin by converting 220 KC to C. This can be obtained as follow:
1 KC = 1000 C
Therefore,
220 KC = 220 KC × 1000 C / 1 KC
220 KC = 220000 C
Next, we shall express 1 minute in second. This is shown below:
1 min = 60 s
Finally, we shall determine the current. This can be obtained as follow:
Charge (Q) = 220000 C
Time (t) = 60 s
Current (I) =?
Q = It
220000 = I × 60
Divide both side by 60
I = 220000 / 60
I = 3666.67 A
Thus, the current flowing through the bulb is 3666.67 A
A pressure of 7x10^5N/m is applied to all surfaces of a copper cube (of sides 25 cm) what is the fractional change in volume of a cube? ( for copper B= 14x10^10N/m)
Answer:
The correct solution is "[tex]5\times 10^{-4}[/tex] %".
Explanation:
The given values are:
Pressure,
[tex]\Delta P=7\times 10^5 \ N/m[/tex]
for copper,
[tex]B=14\times 10^{10} \ N/m[/tex]
As we know,
The Bulk Modulus (B) = [tex]\frac{\Delta P}{-\frac{\Delta V}{V} }[/tex]
or,
The decrease in volume will be:
= [tex](\frac{\Delta V}{V})\times 100 \ percent[/tex]
then,
= [tex]\frac{\Delta P}{B}\times 100 \ percent[/tex]
On putting the values, we get
= [tex]\frac{7\times 10^5}{14\times 10^{10}}\times 100 \ percent[/tex]
= [tex]5\times 10^{-4} \ percent[/tex]
The density of silver is 10.49 g/cm3. If a sample of pure silver has a volume of 12.993 cm3, what is the mass?
Explanation:
Density=mass/volume
mass=x
10.49=X/12.99
X=10.49 X12.99
X=136.29657
mass=136.3g/cm^3
I hope it helped.
NEED HELP A string is fixed at both ends and standing waves with 5 loops are produced. If the length of the string is 60 cm, what is the wavelength of the waves?Single choice.
(2 Points)
6 cm
12 cm
18 cm
24 cm
Answer:
12 cm is the required answer for your question
hope it is helpful to you
Answer: 12
Explanation:
60/5=12
What’s the name of the muscle indicated on the image below?
1.Tricep
2.Oblique
3.Quadricep
4.Trapezius
Answer:
Oblique
Explanation:
I think that's the answer I was told this but forgot if this is the right answer if not then sorry
what is the symbol end unit for electric charge
Answer:
The SI unit of electric charge is the coulomb and is represented by the symbol C.
[tex] \large\sf \leadsto\pmb{ Symbol \: Unit \: For \: Electric \: Charge}[/tex]
[tex] \sf \blue {The \: SI \: unit \: of \: electric \: charge \: is \: coulomb \: which \: is \: also \: represented \: as \: C!}[/tex]
what are the two
factors in which weight of object depends?
Answer:
An object's weight depends on its mass (the amount of matter it consists of) and the strength of the gravitational pull.
Electricity is converted into other forms of _________ such as heat, sound, or light.
Answer:
chemical i think
I hope this helped
NEED HELP The main difference between kinetic energy and potential energy is thatSingle choice.
(2 Points)
kinetic energy involves position, and potential energy involves motion.
kinetic energy involves motion, and potential energy involves position.
although both energies involve motion, only kinetic energy involves position.
although both energies involve position, only potential energy involves motion.
Answer:
kinetic energy involves motion, and potential energy involves position.although both energies involve position, only potential energy involves motion.hope it is helpful to you ☺️☺️✌️
How are wave properties and energy related?
give me examples
Answer:
They don’t ‘represent’ anything, they are properties of the wave.
Depending on the type of wave, we experience them as various phenomena. For example, with a sound wave we experience frequency (or wavelength, which is just another way to describe the same property) as the pitch of the sound. We experience amplitude as the loudness of the sound, although due to the characteristics of the ear, frequency also effects perceived loudness.
If the wave is a light wave, we experience the frequency (wavelength) as the colour of the light, and the amplitude as the brightness of the light.
For many waves, we don’t perceive them at all (e.g. radio waves).
For ocean waves, frequency is the time for each peak or trough to reach us, and amplitude is how tall the wave is.
Please help me ; - ;
Match the food choice with its potential long-term result.
1. eating a piece of cake with 8 grams of fat
2. eating an egg salad sandwich on whole grain bread with 9 grams of fat
3. eating a cheeseburger with 48 grams of fat
A. heart disease
B. obesity
C. weight loss
Answer:
2 = C
3 = B
1 = A
Explanation:
Find the equivalent resistance of this
circuit.
Ri
R2
1002
2002
R3
600 12
Answer:
63016
Explanation:
Ri+R2+R3 this is called series circuit
Answer:
200
Explanation:
100+200=300
1/300+1/600=200
What is the electrical power when the current is 20 amps and the voltage is 15 volts? *
A. 1.33 watts
B. 300 watts
C. 35 watts
Objects in space appear to change position as they orbit the sun. What is this phenomenon called? *
A. Nebular theory
B. Stellar theory
C. Parallax
The moon lacks an atmosphere because its gravity is too STRONG and forces gas molecules into outer space. *
A. True
B. False
Heat pumps move heat from __________ to __________ areas & REQUIRES energy.
A. cold, hot
B. hot, cold
Answer:
The power is 300 watts.
Explanation:
Given that,
Current, I = 20 a
Voltage, V = 15 volts
The electrical power of any device is given by the product of current and voltage. It can be given by :
P = VI
So,
P = 15 × 20
= 300 W
So, the power is 300 watts.
why transparent object don't form a shadow
Explanation:
Transparent objects do not form shadows. The light passes completely from the transparent objects thus these objects will not form shadow. ... In such objects, the light gets refracted thus, such objects forms shadow. The refraction is also the reason why we can see such objects.
Explanation:
cause it pass the light coming from the source of light
Q
16) A student pushes four students on skateboards. She pushes as hard as she can each time. She measures how far each student
goes before stopping. Which is most likely to happen?
A) The biggest student will go the furthest.
B) The smallest student will go the furthest.
c) Each student will go further than the last.
D) All four student will go about the same distance.
Answer:
B
Explanation:
It would be diffrent if on a downward slope but assuming your going straight it would be the smallest student.
The smallest student will go furthest if all the students push with the same amount of force. Therefore, option (B) is correct.
What is Newton's second law of motion?According to Newton’s second law of motion, the force equals the mass of the body times the acceleration of that body when the body has constant mass.
This law states that the acceleration of a body depends on two variables. The first one is the mass of the body and the force acting on the body. The acceleration of a body is directly proportional to the net force acting on the body and inversely proportional to the mass.
Newton’s second law can be expressed in the equation as shown below:
[tex]F= ma[/tex]
or,
[tex]a=\frac{F}{m}[/tex]
Acceleration or gaining speed of a body happens when a force acts on it.
When all four students are pushed by the same amount of force then the acceleration of the smallest student will be greatest as the mass of the smallest student will be least.
Therefore, the smallest student will go furthest in comparison to all other students.
Learn more about Newton's second law of motion, here:
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NEED HELP In which of the following scenarios is work done?Single choice.
(2 Points)
A weightlifter holds a barbell overhead for 2.5 s.
A construction worker carries a heavy beam while walking at constant speed along a flat surface.
A car decelerates while traveling on a flat stretch of road.
A student holds a spring in a compressed position.
Answer: b. A construction worker carries a heavy beam while walking at constant speed along a flat surface.
Explanation:
Answer:
A construction worker carries a heavy beam while walking at constant speed along a flat surface.
hope it is helpful to you
El siguiente esquema representa un objeto con un volumen de 2cm^3 sumergido en un recipiente que contiene agua. La densidad del agua es 1 g/cm^3 . Si solo la mitad del objeto se encuentra sumergido, el valor de la masa del agua desalojada por el objeto es de:
Answer:
Ver explicación
Explanation:
Según los principios de Arquímedes, el empuje hacia arriba de un objeto sumergido en un fluido es igual al peso del fluido desplazado.
Por eso
Empuje hacia arriba = volumen del objeto * densidad del fluido * aceleración debida a la gravedad
Empuje hacia arriba = 2 * 10 ^ -6 / 2 * 1 * 10 ^ 3 * 10
Empuje hacia arriba = 0.01 N
Desde;
Empuje hacia arriba = peso del fluido desplazado
peso del fluido desplazado = 0.01 N
Masa de fluido desplazado = 0.01 N / 10 = 1 * 10 ^ -3 Kg o 1 g