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
Anna [14]
3 years ago
14

A weather emergency siren is mounted on a tower, 105 m above the ground. On one hand, it would be a good idea to make the siren

very loud so that it will warn as many people as possible. On the other hand, safety regulations prohibit the siren from exceeding an intensity level of 101 dB for workers standing on the ground directly below the siren. Assuming that the sound is uniformly emitted, what is the maximum power that the siren can put out
Physics
1 answer:
Svetradugi [14.3K]3 years ago
4 0

Answer:

Explanation:

101 dB = 10.1 B.

Maximum intensity of sound allowed = 10.1 B

Intensity of sound in terms of W/m² can be found as follows

log (I / I₀) = 10.1

I / I₀ = 10¹⁰°¹

I = I₀ X 10¹⁰°¹

= 10⁻¹² X  10¹⁰°¹

= 10⁻¹°⁹ W/m²

105 m above the ground the this intensity will be 105² times

intensity at source point = 10⁻¹°⁹ x 105²

= 138.79 W/m²

energy of sound from source

= 4π times

= 4 x 3.14 x 138.79

= 1743.28W/m²

To calculate in terms of decibel :

log 1743.28 / 10⁻¹²

= log 1743.28 +12

= 15.24 B

= 152.4 dB .

152.4 dB .

You might be interested in
A major difference between AC and DC electricity is that A) the current in AC electricity varies in magnitude and direction. B)
galina1969 [7]

Answer:

A) the current in AC electricity varies in magnitude and direction.

C) the voltage in AC electricity varies in magnitude and direction.

Explanation:

In DC current and voltage the direction of current will not change with time and it always remains the same.

So here in DC voltage and DC current the magnitude may change with time but the direction will always remain same

While in AC voltage and AC current the direction of AC will change with time

periodically.

So here magnitude and direction both will change in AC current and AC voltage.

so the correct answer is

A)     the current in AC electricity varies in magnitude and direction.

C) the voltage in AC electricity varies in magnitude and direction.

7 0
3 years ago
Read 2 more answers
Hey can anyone please help me with this it’s due in few hours and I’m stuck with ittt
Ray Of Light [21]

Answer:

Check body of the explanation

Explanation:

Ooook, quick theory rushdown. if you're at a depth of h in a tank of a fluid, the pressure is the sum of the atmosferic pressure (if the tank is open on top) plus a term which is the product of acceleration of gravity - about 10 ms^-^2, the density of whatever you're sinking in, and the depth at which you are. In formula, p(h) = p_0 + \rho g h, and the pressure is the same for every point of the tank at the same depth.

At this point, we can start answering!

1a. The pressure at A is - not counting atmosferic pressure - 1000 * 10 * 1 = 10^4 Pa, while in B is 1000*10*2 = 2*10^4 Pa, so it's half of it.

1b. The two points are at the same depth, so the pressure is the same - they would be even if the two cilinders weren't linked!

1c. Ditto. Same depth? same pressure!

1d. Usual equation, this time density is 800. Pressure is 800*10*2 = 1,6*10^4 Pa: Since the density is 4/5 of water, the pressure is also 4/5 of the one exerted by water

2a. The volume is simply the product, so 4m*3m*2m = 24m^3

2b. Density is defined as mass over volume, so you simply multiply the volume you found earlier by the density of paraffine: 800* 24 = 1,92 *10^4kg

2c. Weight is defined as the mass of something times the acceleration due to gravity, in our case it's 1.92 *10^4 kg * 10 ms^{-2} = 1.92 * 10^5 N

2d. \rho gh again, what a surprise! 800 {kg \over m^3} * 10 {N \over kg}} * 2 m = 1,6* 10^4 {N\over m^2} =1.6*10^4 Pa

3. Yet again, \rho gh. 1000 {kg \over m^3} * 10 {N \over kg}} * 2 m = 2* 10^4 {N\over m^2} =2*10^4 Pa

4 0
2 years ago
Which of the following involve an increase in the entropy of the system under consideration? a. melting of a solid b. evaporatio
Mama L [17]

Explanation:

Since, entropy is the measure of degree of randomness. So, more randomly the molecules of a substance are moving more will be its entropy.

  • For example, when a solid melts then it means heat is absorbed by it due to which its molecules have gained energy. As a result, they collide with each other and hence, entropy will increase.
  • Evaporation of a liquid will also cause the liquid to change its state from liquid to gas. This means molecules will go far away from each other leading to an increase in the entropy.
  • Sublimation is a process of conversion of a solid into gaseous phase without going through liquid phase. So, in this case also entropy will increase due to gain in energy by the molecules of a solid.
  • In freezing, molecules of a substance come closer to each other and acquire less energy. Hence, entropy decreases.
  • Mixing is a process of combining two or more substances physically with each other. This leads to increase in entropy of a substance.
  • In separation molecules are separated from each other leading to a decrease in energy. Hence, entropy will also decrease.
  • Diffusion is a process in which molecules are able to rapidly move from one place to another. Hence, entropy increases when diffusion takes place.

Thus, we can conclude that melting of a solid, evaporation of a liquid, sublimation, mixing and diffusion involve an increase in the entropy of the system under consideration.

8 0
3 years ago
Mrs. Newman’s class decides to perform an experiment during a class connect session to determine how long it takes different obj
Minchanka [31]

D, all notebooks would hit the floor at the same time. The time it takes to hit the floor is independent of their weight, but rather dependent on the acceleration of gravity. Since gravity is constant, they will all hit the floor at the same time.

4 0
3 years ago
Read 2 more answers
A force of 20N acts upon a body whose weight is 9.8 N. What is the mass of the body and how much is its acceleration?
zloy xaker [14]

Answer:

Explanation:

The two triangles are similar what is the length of DE

7 0
2 years ago
Read 2 more answers
Other questions:
  • If your mass is 63.7 kg, and you are standing 7.5 m away from a boulder with
    7·2 answers
  • A 100 watt incandescent light bulb is operated for 7 hours, and a 32 watt fluorescent light bulb is operated for the same period
    10·1 answer
  • A 4,000-kg car traveling at 20m/s hits a wall with a force of 80,000 N and comes to a stop. What was the impact time?
    14·1 answer
  • HELLLLLLLLLLLLLLLLP QUICKKKKKKKK PLZZZZZ
    5·2 answers
  • A car accelerates at 3 m/s*2. Assuming the car starts from rest, how much time does it need to
    10·2 answers
  • Explain why it is esaier to climb a mountain on a zigzag path rather than one straight up the side. is your increase in gravitat
    14·1 answer
  • You are considering developing a new food-chopping appliance which uses an Arduino with a touchscreen to control the motor. You
    10·1 answer
  • (Q004) During World War II, the military imaged the seafloor by sending pulses of sound waves down through the water and measuri
    9·1 answer
  • Whether microwaves are produced by rotational spectrum​
    11·1 answer
  • Identify the word being referred to choose your answer from the words below​
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!