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
Paraphin [41]
3 years ago
8

A sound from a source has an intensity of 270 db when it is 1 m from the source. what is the intensity of the sound when it is 3

m from the source?
Physics
1 answer:
Lina20 [59]3 years ago
4 0
Sound intensity is inversely proportional to the square of the distance between the source and the receiver.
That is 
I = k/r^2
 where
 k = constant
 r = radius

When r=1,  the intensity is I₁ = k/1 = k
When r=3, the intensity I₂ = k/3² = k/9
Therefore
 I₂ = I₁ /9

In decibels,
I = 10 log₁₀(I/I₀)
where I₀ = reference intensity

When r=1,
10 log₁₀ (I₁/I₀) = 270

When r =3,
10 log₁₀ (I₂/I₀) = 10 log₁₀ [(I₂/I₁)*(I₁/I₀)]
                     = 10 log₁₀ [(1/9)*(I₁/I₀)]
                     = 10 log₁₀(1/9) + 270
                     = 260.5

Answer: 260.5 dB (nearest tenth)
You might be interested in
In a nuclear fusion reaction two 2H atoms are combined to produce one 4He.
Mrrafil [7]

Answer:

a)= 0.025602u

b) = 23.848MeV

c) N = 1.546 × 10¹³

Explanation:

The reaction is

²₁H   +   ²₁H   ⇄   ⁴₂H + Q

a) The mass difference is

Δm = 2m(²₁H) - m (⁴₂H)

       = 2(2.014102u) - 4.002602u

        = 0.025602u

b) Use the Einstein mass energy relation ship

The enegy  release is the mass difference times 931.5MeV/U

E = (0.025602) (931.5)

   = 23.848MeV

c)

the number of reaction need per seconds is

N = Q/E

     = 59W/ 23.848MeV

  = \frac{59}{(23.848 \times 10^6 )(1.6 \times 10^1^9) } \\\\= 1.546 \times 10^1^3

N = 1.546 × 10¹³

5 0
3 years ago
Which equation can be used to model simple harmonic motion
mixer [17]

Answer:x(t)= Acos(wt)

Explanation:

According to Newton's 2nd law,a particle of mass m acted on by a force is given by:Fs=-kx

Where x is displacement from equilibrium

K = spring constant

Therefore X(t) = Acos(2pit/T)

X(t)= Acos(wt)

8 0
4 years ago
A projectile is fired vertically upwards and reaches a height of 78.4 m. Find the velocity of projection and the time it takes t
Musya8 [376]

Answer:

1.) U = 39.2 m/s

2.) t = 4s

Explanation: Given that the

height H = 78.4m

The projectile is fired vertically upwards under the acceleration due to gravity g = 9.8 m/s^2

Let's assume that the maximum height = 78.4m. And at maximum height, final velocity V = 0

Velocity of projections can be achieved by using the formula

V^2 = U^2 - 2gH

g will be negative as the object is moving against the gravity

0 = U^2 - 2 × 9.8 × 78.4

U^2 = 1536.64

U = sqrt( 1536.64 )

U = 39.2 m/s

The time it takes to reach its highest point can be calculated by using the formula;

V = U - gt

Where V = 0

Substitute U and t into the formula

0 = 39.2 - 9.8 × t

9.8t = 39.2

t = 39.2/9.8

t = 4 seconds.

7 0
4 years ago
The object distance for a concave lens is 8.0 cm, and the image distance is 12.0 cm. The height of the object is 4.0 cm. What is
swat32
The answer for this question, If I am correct, should be answer "D".
3 0
3 years ago
Read 2 more answers
The air also contained a small amount of argon.
andriy [413]

Answer:

When argon changes from a gas to a liquid, the forces between the molecules become stronger so the particles become closer together and come into come into contact more often. The particles move at a less faster rate as the have less kinetic energy due to decrease in temperature. When argon changes from a liquid to a solid, the forces become even stronger so the particles are arranged in fixed positions and vibrate around a fixed point as they cannot move past each other

8 0
2 years ago
Other questions:
  • Carlos is baking a cake. The last step in the directions is to put the cake batter in the oven. Why does Carlos need to put the
    5·2 answers
  • An object is at rest on an inclined plane. In which direction does the static friction force act?
    14·1 answer
  • What is the average velocity of atoms in 1.00 mol of neon (a monatomic gas) at 288k?
    10·1 answer
  • What is the structure of a magnet?
    11·1 answer
  • What are different type of plastids explain them?​
    10·1 answer
  • Open the attached image to see the question.
    10·1 answer
  • Solar-powered cars use energy from the Sun to work. A panel on the car absorbs light energy from the Sun, which
    15·2 answers
  • Will mark brainlist<br> THANKS!
    13·1 answer
  • Can anyone heelp me pls
    8·2 answers
  • Find the odd one out radish,potato, beet,carrot.​
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!