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
erica [24]
3 years ago
15

A student is standing 8 m from a roaring truck engine that is measured at 20. The student moves 4 m closer to the engine. What i

s the measured sound intensity at the new distance?.
Physics
2 answers:
dangina [55]3 years ago
8 0

By knowing how intensity relates to distance, we will see that at 4 meters of the engine the intensity is 80.

<h3>How sound intensity relates to distance?</h3>

The sound spreads in a solid angle like all waves, so the intensity of the sound will decrease with the distance squared, this means that:

I = \frac{P}{4*pi*r^2}

Where P is the sound power, we know that when the student is at 8m from the engine, the intensity measured is 20 (it does not tell the units) so we have:

20 = \frac{P}{4*3.14*(8m)^2} \\\\P = 20*4*3.14*(8m)^2 = 16,078.8 m^2

Now, if you move 4 meters closer to the engine, your new position will be:

r = 4m

Then we have:

I = \frac{16,078.8 m^2}{4*3.14*(4m)^2} = 80

If you want to learn more about sound intensity, you can read:

brainly.com/question/26376755

andrezito [222]3 years ago
4 0

Answer:

80 is the answer! 100% CORRECT!

Explanation:

<em>~Hope this helps! :)</em>

You might be interested in
What is the kinetic energy of a 478 kg object that is moving with the speed of 15 m/s
Tpy6a [65]
Kinetic energy = (1/2)*mass*velocity^2
KE = (1/2)mv^2
KE = (1/2)(478)(15)^2
KE = 53775J
5 0
3 years ago
When you hit a .27 kg volleyball the contact time is 50 ms and the average force is 125 N. If you serve the volleyball (from res
yulyashka [42]

(A) P(v) = 0.135v

(B) P(h) = 0.234v

<u>Explanation:</u>

Given-

Mass of the ball, m = 0.27kg

Force, F = 125N

angle of projection, θ = 30°

Let v be the velocity of the ball.

A) vertical component of the momentum of the volleyball

We know,

P(vertical) = mvsinθ

P(V) = 0.27 X v X sin 30°

P(V) = 0.27 X v X 0.5

P(V) = 0.135v

B) horizontal component of the momentum of the volleyball

We know,

P(Horizontal) = mvcosθ

P(h) = 0.27 X v X cos 30°

P(h) = 0.27 X v X 0.866

P(h) = 0.234v

8 0
3 years ago
100 points!!! Please help!!!
Greeley [361]

Answer:

41°

Explanation:

Kinetic energy at bottom = potential energy at top

½ mv² = mgh

½ v² = gh

h = v²/(2g)

h = (2.4 m/s)² / (2 × 9.8 m/s²)

h = 0.294 m

The pendulum rises to a height of  above the bottom.  To determine the angle, we need to use trigonometry (see attached diagram).

L − h = L cos θ

cos θ = (L − h) / L

cos θ = (1.2 − 0.294) / 1.2

θ = 41.0°

Rounded to two significant figures, the pendulum makes a maximum angle of 41° with the vertical.

7 0
4 years ago
How much force, in g cm/s2
scoray [572]
In this question force is measured in  g cm/s2 so we know that to get the answer we times g by cm/s2 
50 × 20 = 1000
3 0
4 years ago
Read 2 more answers
Calculate the change in length of a 90.5 mm aluminum bar that has increased in temperature by from -14.4 oC to 154.6 oC
nignag [31]

Answer:

 ΔL = 3.82 10⁻⁴ m

Explanation:

This is a thermal expansion exercise

          ΔL = α L₀ ΔT

          ΔT = T_f - T₀

where ΔL is the change in length and ΔT is the change in temperature

Let's reduce the length to SI units

          L₀ = 90.5 mm (1m / 1000 mm) = 0.0905 m

let's calculate

          ΔL = 25.10⁻⁶ 0.0905 (154.6 - (14.4))

          ΔL = 3.8236 10⁻⁴ m

     

using the criterion of three significant figures

          ΔL = 3.82 10⁻⁴ m

5 0
3 years ago
Other questions:
  • A Fathom is an old depth measure equal to 6 Feet How deep in meters is a 5_ fathom deep water channel​ show working out
    8·1 answer
  • Large numbers of ribosomes are present in cells that specialize in producing which molecules?
    9·1 answer
  • The sun is 1.5 × 108 km from Earth. The index of refraction for water is 1.349. How much longer would it take light from the sun
    5·1 answer
  • Density is equal to
    9·1 answer
  • What will most likely happen if a sound wave moves from the air through a solid?
    12·2 answers
  • A 66.0-kg boy and his 45.0-kg sister, both wearing roller blades, face each other at rest. The girl pushes the boy hard, sending
    11·1 answer
  • 1. The saw cut that is made at 450-75° angles to the annual rings is called:
    12·1 answer
  • Helppp pls yes or no question
    11·2 answers
  • Rafael is driving his car at 26 m/s. What is the shortest distance in which he can brake and stop if the coefficient of static f
    15·1 answer
  • A wave travels at 1,500 m/s with a frequency of 5 hertz. What is its wavelength?
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!