The sound intensity at 4 m from a source is 100 W/me. What is the intensity of the sound at 12 m away from the source ?

Answers

Answer 1

Answer:

Intensity at 12 meters will be 11.11 W/m^2

Explanation:

Recall that the intensity of sound is inversely proportional to the square of the distance from the source. Therefore, if at 4 m the intensity is 100 W/m^2

we have: 100 W/m^2 = k/16 and therefore, k = 1600 W

Then the intensity (I) at 12 m will be:

I = k/12^2 = 1600/144  W/m^2 = 11.11 W/m^2


Related Questions

Describe and give an example of mutualism.


Describe and give an example of commensalism.


Describe and give an example of parasitism.


Describe and give an example of competition.


Describe and give an example of predation.

Answers

Answer:

Mutualism - Bee to flower. Bee eats - flower reproduces

Commensalism - Tree Frog to plant or tree. Frog uses plant for protection.

Parasitism - Flea or tick to host. Parasite feeds off host.

Explanation:

Competition - relationship between organisms that strive for same resources. intraspecific and interspecific. ex) two males competing for mates.

predation - one organism kills and consumes another. wolf hunting moose, cat hunting mouse. venus fly trap killing insect

A 45 kg object has a momentum of 225 kg-m/s northward. What is the object's velocity?
A. 180 m/s
B. 5.0 m/s
C. 10,125 m/s
D. 0.20 m/s

Answers

The answer is 5.0 m/s

A golfer hits the ball off the tee at an angle of thirty-five degrees from the horizontal with a speed of 46 m/s. It lands on the green, which is elevated 5.50 m higher than the tee. How much time elapsed from when the ball was hit to when it landed on the green?

Answers

Answer:

t = 5.16 seconds.

Explanation:

The flight time can be found using the following equation:

[tex] y_{f} = y_{0} +v_{0y}*t - \frac{1}{2}gt^{2} [/tex]

Where:

t: is the time

g: is the gravity = 9.81 m/s²

y₀: is the initial height = 0

[tex]y_{f}[/tex]: is the final height = 5.50 m

[tex]v_{0y}[/tex]: is the initial vertical velocity = v*sin(35)

v: is the speed = 46 m/s

[tex] 5.50 = 46*sin(35)*t - \frac{1}{2}9.81*t^{2} [/tex]

By solving the above cuadratic equation we have:

t₁= 0.22 s and t₂= 5.16 s      

We will take the solution equal to 5.16 seconds, since in 0.22 seconds (very short time) the ball is going up and in 5.16 seconds it landed on the green.                        

 

Therefore, 5.16 seconds have passed since the ball was hit until it landed.

I hope it helps you!                                                                                            

At an accident scene on a level road, investigators measure a car's skid mark to be 98 m long. It was a rainy day and the coefficient of friction was estimated to be 0.38. a) Use these data to determine the speed of the car when the driver slammed on (and locked) the brakes.b) Why does the car's mass not matter?

Answers

Answer:

a. V = 19.1m/s

b. The mass of the car does not matter

Explanation:

A.

KE = 1/2mv² = fd --------(1)

Fd = umgd ---------(2)

Therefore,

1/2mv² = umgd ---------(3)

M will cancel itself out from both sides of equation 3.

Then we will have:

1/2v² = ugd

Then we cross multiply to make v² the subject of the formula

V² = 2ugd

V = √2ugd -------(4)

U = 0.38

g = 9.81

d = 98

When we input these values into equation 4, we will have:

V = √2x0.38x9.81x98

V = √730.6488

V = 27.03m/s

B.

The mass of the car does not actually matter as the mass was cancelled out on the both sides of equation 3

A radio signal has a frequency of 1.023 x 108 HZ. If the speed of the signal in air is 2.997 x 108m/s, what is the wavelength of the signals? а 7.15 m b 5.23 m C 2.93 m d 0.93 m​

Answers

Answer:

2.93 m  (which agrees with answer "C" on the list)

Explanation:

Recall that the speed of the wave equals the product of the wave's length times its frequency. Therefore, the wavelength is going to be the quotient of the speed of the signal divided its frequency:

Wavelength = 2.997  10^8 / 1.023  10^8 =  2.93 m

Mr Johnson launches an arrow horizontally at a rate of 40m/s off of a 78.4 m cliff towards the south, how much time does it take before the arrow hits the ground below (step 1 of a quesiton will need this answer for a future question)
a 2 seconds
b. 1 second
c.4 seconds
d 19.6​

Answers

Answer:c

Explanation:

Which of the following best describes a solid?
A
matter is made of atoms so tightly packed together that they cannot move around
B
takes the shape and volume of its container
C
has a definite volume, but takes the shape of its container

Answers

The answer to the question is A.
A is the correct answer

Suppose the flow rate of blood in a coronary artery has been reduced to half its normal value by plaque deposits. By what factor has the radius of the artery been reduced, assuming no turbulence occurs?
Strategy
Assuming laminar flow, Poiseuilleâs law states that
Q = (p2 - p1)pir^4/8nl.We need to compare the artery radius before and after the flow rate reduction.

Answers

Answer:

1.18

Explanation:

The flow rate of blood is proportional to the fourth power of its radius as given the Poiseuille's law.

The law is :

[tex]$Q \propto r^4$[/tex]

It is given here that the flood flow rate is been reduced to half its normal value. Therefore, [tex]$Q_1 = \frac{1}{2}Q_2$[/tex]

So, for the radius [tex]$r_1$[/tex] and [tex]$r_2$[/tex], the ratios of their flow rates are :

[tex]$\frac{Q_1}{Q_2}=\frac{r_1^4}{r_2^4}$[/tex]

It is given that the flow rate is reduced to half. So we have,

[tex]$\frac{Q_1}{2Q_1}=\frac{r_1^4}{r_2^4}$[/tex]

or [tex]$r_2=2^{1/4}{r_1}$[/tex]

[tex]$r_2=1.18 \ r_1}$[/tex]

So the radius changes by a factor of 1.18

A car accelerates steadily from 15 m/s to 25 m/s in 5 s. what us its speed​

Answers

8 mph ? i have no idea .

What is the magnitude and direction of the magnetic force on the bob at the lowest point in its path, if it has a positive 0.250 μC charge and is released from a height of 30.0 cm above its lowest point? The magnetic field strength is 1.50 T.

Answers

Answer:

[tex]F=9.09\times 10^{-7}\ N[/tex]

Explanation:

Given that,

Charge, q = 0.250 μC

It is released from a height of 30 cm or 0.03 m

The magnetic field strength is 1.50 T.

First we find the velocity using the conservation of energy as follows :

[tex]mgh=\dfrac{1}{2}mv^2\\\\v=\sqrt{2gh} \\\\v=\sqrt{2\times 9.8\times 0.3} \\\\v=2.424\ m/s[/tex]

Now, the magnetic force is given by :

[tex]F=qvB\\\\=0.25\times 10^{-6}\times 2.424\times 1.5\\\\=9.09\times 10^{-7}\ N[/tex]

So, the magnetic force is [tex]9.09\times 10^{-7}\ N[/tex]. Since, the bob is at the lowest point, the direction of the magnetic force at the lowest point is upward.

A 36.3 kg cart has a velocity of 3 m/s. How much kinetic energy does the object have?

Answers

Answer:

163.35

__________________________________________________________

We are given:

Mass of the object (m) = 36.3 kg

Velocity of the object (v) = 3 m/s

Kinetic Energy of the object:

We know that:

Kinetic Energy = 1/2(mv²)

KE = 1/2(36.3)(3)²            [replacing the variables with the given values]

KE = 18.15 * 9

KE = 163.35 Joules

Hence, the cart has a Kinetic Energy of 163.35 Joules

5. How does the existence of humans compare with Earth's age?

Answers

Answer:

Human activity has fundamentally changed our planet. We live on every continent and have directly affected at least 83% of the planet’s viable land surface. Our influence has impacted everything from the makeup of ecosystems to the geochemistry of Earth, from the atmosphere to the ocean. Many scientists define this time in the planet’s history by the scale of human influence, and label it as a new geological epoch called the Anthropocene.

Explanation:


A material that provides resistance to the flow of electric current is called a(n):

circuit

conductor

insulator

resistor

Answers

Answer:

it's an insulator

Explanation:

Insulators provides resistance

Answer:

C. insulator

Explanation:

A 40-cm-diameter, 300 g beach ball is dropped with a 4.0 mg ant riding on the top. The ball experiences air resistance, but the ant does not. What is the magnitude of the normal force exerted on the ant when the ball's speed is 4.0 m/s?

Answers

Answer:

The normal force exerted on the ant is 0.75 N.

Explanation:

Given;

diameter of the ball, D = 40 cm = 0.4m

radius of the ball, r = 0.2m

mass of the beach ball, m₁ = 300 g = 0.3 kg

mass of the ant, m₂ = 4 x 10⁻⁶ kg

speed of the ball, v = 4 m/s

The area of the ball, assuming spherical ball is given by;

A = 4πr²

A = 4π(0.2)² = 0.5027 m²

The drag force (resistance) experienced by the spherical ball is given as;

[tex]F_D = \frac{1}{2}C\rho Av^2[/tex]

where;

C is the drag coefficient of the spherical ball = 0.45

ρ is density of air = 1.21 kg/m³

[tex]F_D = \frac{1}{2}C\rho Av^2\\\\F_D = \frac{1}{2}(0.45)(1.21) (0.5027)(4)^2\\\\F_D = 2.19 \ N[/tex]

The downward force of the ball due to its weight and that of the ant is given by;

[tex]F_g = mg\\\\F_g =g(m_{ant} + m_{ball})\\\\F_g = g(4*10^{-6} \ kg\ + \ 0.3\ kg)\\\\F_g = g(0.300004 \ kg) \ \ \ (mass \ of \ the \ ant \ is \ insignificant)\\\\F_g = 9.8(0.3)\\\\F_g = 2.94 \ N[/tex]

The net downward force experienced by the ball is given by;

[tex]F_{net} = F_g - F_D\\\\F_{net} = 2.94 \ N - 2.19 \ N\\\\F_{net} = 0.75 \ N[/tex]

This downward force experienced by the ball is equal to the normal reaction it exerts on the ant.

Thus, the normal force exerted on the ant is 0.75 N.

Rita places a 2.5 kg block on a frictionless inclined plane that is 30 degrees above horizontal. She applies a horizontal force, which keeps the block from moving up or down the inclined plane. What is the magnitude of the force Rita applies?​

Answers

Answer:

14.2

Explanation:

find horizontal force of the weight = 2.5kg x 9.8 Sin30 = 12.3 N

to prevent the sliding she needs to pull horizontally

Fh = 12.3 /Cos 30 =14.2N

A car is traveling west for 12 s its speed is 36.12 m/s in the same direction find the total distance the car traveled

Answers

We are given:

constant speed of the car (u) = 36.12 m/s

time in question (t) = 12 seconds

Solving for the Distance and Displacement:

from the second equation of motion:

s = ut + 1/2 at^2

since we have 0 acceleration:

s = ut

replacing the variables

s = 36.12 * 12

s = 433.44 m

Since the car is travelling in a straight line towards the same direction, it's Distance will be equal to its Displacement

Hence, both the Displacement and Distance covered by the car is

433.44 m

but since Displacement also has a direction vector along with it,

the Displacement will be  433.44 m due west

What are the things being compared in the following argument?



"The United Nations failed to intervene in Bosnia to prevent massive human rights violations and ethnic cleansing. It also failed to act to stop the murders of close to a million innocent people in Rwanda. THe UN will not intervene to stop any widespread slaughter of innocents in Nigeria."

a.
Ethnic cleansing in Nigeria and Bosnia

b.
The slaughter of innocents by the UN

c.
situations in which the United Nations might intervene

d.
Human rights violations in Rwanda and Bosnia

Answers

Answer:

C

Explanation:

The thing that is being compared in the given argument is Ethnic cleansing in Bosnia. The correct option is A.

What is Ethnic cleansing?

Ethnic cleansing is the systematic removal of ethnic, racial, and religious groups from a given area with the goal of ethnically homogenizing the region.

In this group of resettled Bosnian refugees, ethnic cleansing has resulted in high rates of PTSD and depression, as well as other forms of psychological morbidity.

The long-term consequences of ethnic cleansing as a form of mass psychological trauma have yet to be studied.

Political elites seek to gain and/or consolidate political power by capitalizing on nationalism and the desire to create the domestic "other" in order to foster solidarity among the dominant nationality.

The topic under discussion in this argument is ethnic cleansing in Bosnia.

Thus, the correct option is A.

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A potential difference of 1.20 V will be applied to a 33.0 m length of 18-gauge copper wire (diameter = 0.0400 in.). Calculate (a) the current, (b) the magnitude of the current density, (c) the magnitude of the electric field within the wire, and (d) the rate at which thermal energy will appear in the wire.

Answers

Answer:A) Current = 1.739A, B)current density, J = 2.147x10^6 A/m2

magnitude of electric field , E =  0.036 N/C

)rate of thermal energy, P  =2.086W

Explanation:

Resistance  = R =   ρL/A

But the cross-section area of the wire. is given as

Diameter / 2 = 0.04/2 =0.02in to m = 0.02 / 39.37= 0.000508

A = πr^2 = π x  0.000508^2 = 8.10 x 10^-7

since resistivity of copper,ρ= 17x10-9 ohm.m

so resistance is   R =   ρL/A

17x10-9  x 33 / 8.1x10-7

= 0.69 ohm.

A) Current =    I = Voltage /Resistance =1.20/0.69 =1.739A

B)current density, J = Current /Area

= 1.739/8.1x10-7

= 2.147x10^6 A/m2

c)magnitude of electric field , E =  Current density x resistivity =J ρ

E = 2.147 x 10^6  x 17  x 10^-9

E = 0.036 N/C

D)rate of thermal energy, P  = I² R =1.739² X 0.69

=2.086W

Why do stretching exercises increase flexibility more than cardio exercises?

Answers

cardio exercise improve the strength of the limbs. C.) cardio exercises consist of fluid movements. D.) carido exercises depend on increased oxygen ...

The image blow shows a certain type of global wind:
What best describes these winds? Polar easterlies caused by air above poles being relatively warmer.
Polar easterlies caused by air above poles being relatively cooler.
Trade winds caused by air above equator being relatively warmer.
Trade winds caused by air above equator being relatively cooler.​

Answers

Answer:

i got u its a

Explanation:

1. When an object is at rest, not moving, and is crashed into by another
object...which object is experiencing a force and in what direction? Or are
both experiencing a force - what direction?

Answers

Answer:

both experience forces or at least a force

Explanation:

it would go in the direction the other object

(second object, the one that crashed) was going

si if going right then right if left then left

plus or minus

The chart shows Daniela’s run through her race.

A graph with horizontal axis time (seconds) and vertical axis position in (meters). The line runs straight from 0 seconds 5 meters to 10 seconds 30 meters.
What is her velocity?

1.5 m/s
2 m/s
2.5 m/s
5 m/s

Answers

Answer:

Explanation:

velocity is the rate of change of displacement with respect to time.

Velocity = displacement/time

If a  line runs straight from 0 seconds 5 meters to 10 seconds 30 meters.

The velocity will be expressed as;

v = d2-d2/t2-t1

v = 30-5/10-0

v = 25/10

v = 2.5m/s

Hence her velocity is 2.5m/s

Daniela's velocity is 2.5 m/s.

Velocity is the ratio of displacement to time taken. It is given by:

Velocity = displacement / time

The velocity of Daniela can be gotten by calculating the slope of the graph. Considering the points (0, 5) and (4, 15).

[tex]Velocity(slope)=\frac{15-5}{4-0}=2.5\ m/s[/tex]

Therefore Daniela's velocity is 2.5 m/s.

Find out more at: https://brainly.com/question/17127206

what do we call the games that involve different manipulation skills like throwing,tossing,rolling,catching,running,jumping,hopping and stretching what is the answer A.puzzle game B.simulation games C.target games D.role-playing games​

Answers

i think its C not sure tho

Based on the situation above, choose the CORRECT type of error.

The reading from the timer was not accurate because some of
the timer's display was missing and broken."​

Answers

Answer:

what's your question I can't understand

A 60-W light bulb emits spherical electromagnetic waves uniformly in all directions. If 50% of the power input to such a light bulb is emitted as electromagnetic radiation, what is the radiation intensity at a distance of 2.00 m from the light bulb?
A) 15 W/m2
B) 4.8 W/m2
C) 2.4 W/m2
D) 0.60 W/m2
E) 1.2 W/m2

Answers

Answer:

a

Explanation:

A 60-W light bulb emits spherical electromagnetic waves uniformly in all directions. If 50% of the power input to such a light bulb is emitted as electromagnetic radiation, what is the radiation intensity at a distance of 2.00 m from the light bulb    

so i did 60(50%)=30÷2=15

The radiation intensity is 15 W / m².

To find the radiation intensity, the values are given as,

Power = 60 W

Distance = 2 m

50% of the power input is emitted as electromagnetic radiation.

What is  radiation intensity?

      The amount of energy emitted per unit solid angle by per unit area of the radiating surface can be said as radiation intensity.

     As, when there is a power output, the input power will emit some energy as a kinetic energy and electromagnetic radiation. By the way, the power input emits 50 % as a radiation, so the power input given as,

                   P = 60 / 2 ( As it was 50 % )

                      = 30 Watt.

The radiation intensity is,

                In = 30 / 2

                    =  15 W / m².

Thus, the radiation intensity is calculated as, 15 W/ m².

So, Option A is the correct answer.

Learn more about radiation intensity,

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Explane Hawaii characteristics

Answers

Answer:

Hawaii is located in the Pacific Ocean to the southwest of the continental U.S., southeast of Japan and northeast of Australia. Hawaii is known for its tropical climate, unique topography, and natural environment, as well as its multicultural population.

An electric motor spins at a constant 2695.0 rpm. If the rotor radius is 7.165 cm, what is the linear acceleration of the edge of the rotor?A) 5707 m/s^2 B) 281.6 m/s^2 C) 28.20 m/s^2 D) 572,400 m/s^2

Answers

Answer:

5707 m/s^2

Explanation:

Test Due! Which statement is true?

Answers

The correct answer is C. Mercury and Mars have the same gravitational force

Explanation:

This chart compares the different features of two planets in our solar system (Mercury and Mars). In this chart, the only numerical value or feature that is the same for both planets is gravity because for both planets gravity is 1.7 m/s2. This implies the gravitational force or the force that attracts objects towards the center of the planet is the same or that objects are pulled with the same force in both planets. Moreover, this factor depends on others such as mass, density, among others.

What two methods are the best choices to factor this expression 18x2-8

Answers

Answer:

Please check the explanation

Explanation:

The best two methods will be:

Factor by groupingFactor out the GCF

Factor by grouping

Factor by grouping deals with establishing a smaller groups from each term.

[tex]18x^2=\:\left(2\cdot 3\cdot 3\cdot x^2\right)[/tex]

[tex]8\:=\:\:2\cdot 2\cdot 2[/tex]

Therefore, the expression becomes

[tex]18x^2=\:\left(2\cdot 3\cdot 3\cdot x^2\right)-\left(2\cdot \:2\cdot \:2\right)[/tex]

Now factor out the greatest common factor (GCF) which is 2

         [tex]=\:2\left(3\cdot \:\:3x^2-\left(2\right)\left(2\right)\right)[/tex]

           [tex]=2\left(9x^2-2\cdot \:2\right)[/tex]

            [tex]=2\left(9x^2-4\right)[/tex]

Factor out the GCF

Given the expression

[tex]18x^2-8\:\:\:[/tex]

factor out common term 2

[tex]=2\left(9x^2-4\right)[/tex]

[tex]=2\left(3x+2\right)\left(3x-2\right)[/tex]          ∵ [tex]Factors\:\:\left(9x^2-4\right)=\left(3x+2\right)\left(3x-2\right)[/tex]

What is the Poynting vector S⃗ (x,t)S→(x,t), that is, the power per unit area associated with the electromagnetic wave described in the problem introduction

Answers

Answer:

[tex]\mathbf{S^{\to} (x,t) = \dfrac{{E_o} {B_o}}{\mu_o} sin^2 (kx -wt) \hat i }[/tex]

Explanation:

Consider:

[tex]E^{\to} =E_o \ Sin (kx - wt) \hat j[/tex]

[tex]B^{\to} =B_o \ Sin (kx - wt) \hat k[/tex]

The equation for the Poynting vector is given as:

[tex]S^{\to} (x,t) = \dfrac{E^{\to}\times B^{\to}}{\mu_o}[/tex]

[tex]S^{\to} (x,t) = \dfrac{E_o \ Sin(kx - wt) \hat j \times B_o sin (kx -wt) \hat k}{\mu_o}[/tex]

[tex]S^{\to} (x,t) = \dfrac{{E_o} {B_o}}{\mu_o} sin^2 (kx -wt) (\hat j \times \hat k)[/tex]

[tex]S^{\to} (x,t) = \dfrac{{E_o} {B_o}}{\mu_o} sin^2 (kx -wt) \hat i[/tex]

[tex]\mathbf{S^{\to} (x,t) = \dfrac{{E_o} {B_o}}{\mu_o} sin^2 (kx -wt) \hat i }[/tex]

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