1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Oksi-84 [34.3K]
3 years ago
15

A stereo speaker is placed between two observers who are 35 m apart, along the line connecting them. If one observer records an

intensity level of 64 dB, and the other records an intensity level of 85 dB, how far is the speaker from each observer
Physics
1 answer:
kompoz [17]3 years ago
8 0

Answer:

   x = 2,864 m ,       Ra = 32.1 m                       

Explanation:

Let's solve this problem in parts, let's start by finding the intensity of the sound in each observer

observer A β = 64 db

             β = 10 log Iₐ / I₀

where I₀ = 1 10⁻¹² W / m²

              Iₐ = I₀ 10 (β/ 10)

let's calculate

              Iₐ = 1 10⁻¹² (64/10)

              Iₐ = 2.51 10⁻⁶ W / m²

Observer B β = 85 db

             I_b = 1 10-12 10 (85/10)

             I_b = 3.16 10⁻⁴ W / m²

now we use that the emitted power that is constant is the intensity over the area of ​​the sphere where the sound is distributed

              P = I A

therefore for the two observers

              P = Ia Aa = Ib Ab

the area of ​​a sphere is

               A = 4π R²

we substitute

               Ia 4pi Ra2 = Ib 4pi Rb2

               Ia Ra2 = Ib Rb2

Let us call the distance from the observer be to the haughty R = ax, so the distance from the observer A to the haughty is R = 35 ax; we substitute

             Ia (35 -x) 2 = Ib x2

we develop and solve

           35-x = Ra (Ib / Ia) x

           35 = [Ra (Ib / Ia) +1] x

           x (11.22 +1) = 35

           x = 35 / 12.22

            x = 2,864 m

This is the distance of observer B

The distance from observer A

            Ra = 35 - x

            Ra = 35 - 2,864

            Ra = 32.1 m

You might be interested in
An internal combustion engine uses fuel, of energy content 44.4 MJ/kg, at a rate of 5 kg/h. If the efficiency is 28%, determine
Fudgin [204]
Efficiency =  Power Output / Power Input

Power Input = Rate of Energy input = 44.4 MJ/kg * 5 kg/h

 = 222 MJ/h

But 1 hour = 3600seconds

222 MJ/h = 222 MJ/3600s =  0.061667 MW              J/s = Watts

Power input = 0.061667 MW = 61 667 W

From  Efficiency =  Power Output / Power Input

   28% =  Power Output / 61667

   Power Output = 0.28 * 61667

   Power Output = 17266.76 W
 
  Power Output = 17 267 W

 Rate of heat Rejection = Power input - Power output

                                        = 61667 - 17267 = 44400 W

Rate of heat Rejection = 44 400 W.


C- Copyright.
5 0
3 years ago
The speed of sound in ice, water, and steam is shown. What best explains the speed of sound in different states of matter?
Marina86 [1]

The speed of sound is greater in ice (4000 m/s), then in water (1500 m/s), then in air (340 m/s). The explanation for this is the differente state of the matter in the three cases.

In fact, sound waves travel faster in solids (like ice), then in liquids (like water), then in gases (like air). This is because the speed of the sound wave depends on the density of the medium: the greater the density, the faster the sound wave. This can be easily understood by thinking at how a sound wave propagates: a sound wave is a vibration of molecules, which is transmitted throughout the medium by collision of the molecules. Therefore, the smaller the spacing between the molecules (such as in solids), the more efficient is the propagation, and so the sound wave is faster. On the contrary, there is a large spacing between molecules in gases (such as in the air), so there are less collisions between the molecules and so the wave is not transmitted efficiently, and so it has less velocity.

5 0
4 years ago
Read 2 more answers
Which of the following is true of changes in momentum?
soldi70 [24.7K]

Answer: ⇒  Answer is 3

<h2>Explanation: momentum = mass × velocity</h2>

"A small force may produce a large change in momentum by acting on a very massive object".

THEY HAVEN'T GIVEN US THE TIME PERIOD NOR THE DISTANCE TRAVELED. THEREFORE WE CANNOT ACTUALLY DECIDE IF THE FORCE IS KEPT FOR A LONG TIME OR SHORT TIME. ANYWAYS SINCE THE MASS IS GIVEN AS MASSIVE , THE  MOMENTUM SHOULD BE DEFINITELY HIGH.

WHY I SAY OTHERS ARE WRONG:

1) For a small force to give a large change in momentum, it should act for a long time interval.

2) By applying a large force for a short time interval, the change of momentum should be large.

3) Correct answer.

4) Acting over a short distance can be the same as acting over a short period of time.Therefore the distance should be large in order for a larger momentum.

I HOPE IT HELPS!

6 0
3 years ago
How to find wavelength
Andrews [41]
If the wavelength<span> is given, the energy can be determined by first using the wave equation (c = λ × ν) to </span>find<span> the frequency, then using Planck's equation to </span>calculate<span> energy. Use the equations above to answer the following questions. 1. Ultraviolet radiation has a frequency of 6.8 × 1015 1/s.</span>
4 0
3 years ago
How does mass differ from weight? List 2 differences.
Alinara [238K]

weight is vector vary from place to place

5 0
3 years ago
Read 2 more answers
Other questions:
  • The water at the top of a waterfall has _____ energy.
    6·2 answers
  • 1. What quantity of heat is required to raise
    14·1 answer
  • A pair of narrow, parallel slits separated by 0.254 mm are illuminated by green light of wavelength 559 nm. An interference patt
    6·1 answer
  • Work and energy both have the unit?
    12·1 answer
  • Reeti has a mass of 51.0 kg. The Gravitron, a ride that spins so fast that the floor can be removed without the riders falling,
    13·1 answer
  • An atom with a positive charge is an anion.<br> a. true<br> b. fals
    14·1 answer
  • A rotating wheel requires a time Δt = [01]_____________________ to rotate 37.0 revolutions. Its angular speed at the end of the
    10·1 answer
  • Which two conditions would result in the strongest electric force between charged objects
    15·2 answers
  • How does heat transfer? (Think temperature)​
    10·1 answer
  • What is the density of an object if it has a volume of 162 ml with a mass(273) that is shown in the picture below?
    10·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!