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Readme [11.4K]
3 years ago
6

At a distance 30 m from a jet engine, intensity of sound is 10 W/m^2. What is the intensity at a distance 180 m?

Physics
1 answer:
AleksandrR [38]3 years ago
5 0

Answer:

I_{2}=0.27 W/m^2

Explanation:

Intensity is given by the expresion:

I_{2}=Io (\frac{r1}{r2} )^{2}

where:

Io = inicial intensity

r1= initial distance

r= final distance

I_{2}=10 W/m^2 (\frac{30m}{180m} )^{2}

I_{2}=0.27 W/m^2

You might be interested in
Which of the following statements correctly describes the index of refraction of a material? Select all that apply.
mote1985 [20]

Answer:

Option C and D only

Explanation:

Option A is incorrect  because refractive index of a material is the ratio of speed of light in vacuum to the speed of light in a any given medium

Option B is correct as the speed of light in vacuum is always greater than the speed of light in any given medium.

Option C is correct

Option D is incorrect

Option E is incorrect because the denser the medium the more is the refractive index. Water is denser than air, hence it should have more refractive index as compared to that of air.

4 0
3 years ago
7. A car moving at 10m/s (about 22.4 mph) crashes into a barrier and stops in 0.25 m.
Galina-37 [17]

Answer:

a) 0.05s

b) 4000N

Explanation:

a)When car is stopped its final velocity become zero

U- 10 m/s

V- 0 m/s

S - 0.25 m

t -?

S = (v+u)*t/2

0.25 =(10+0)*t/2

t = 0.05s

b) If we happened to calculate the avarage force we have to consider about acceleration

V= 0

U = 10

t = 0.05 s

a =?

V = U + at

0 = 10 -a * 0.05

a = 200 m/s2

F = m *a

= 20 * 200

= 4000N

6 0
3 years ago
What is the guage pressure of an object with a mass of 30 kg and 5ft height?
wariber [46]

Answer: D=pg

Explanation:

?????

8 0
3 years ago
A car of mass 487 kg travels around a flat, circular race track of radius 53.3 m. The coefficient of static friction between the
aleksklad [387]

Answer:

9.96 m/s

Explanation:

mass of car, m = 487 kg

radius of track, R = 53.3 m

coefficient of static friction, μ = 0.19

acceleration due to gravity, g = 9.8 m/s^2

let v be the maximum speed so that the car can go without flying off the track.

The formula for the maximum speed is given by

v_{max}=\sqrt{\mu Rg}

v_{max}=\sqrt{0.19\times53.3\times9.8

vmax = 9.96 m/s

8 0
3 years ago
the two ropes are used to vertically lower a 255 kg piano from exactly 4 m form a seocnd sotry window to the ground how much wor
Ilya [14]

Complete Question

The Question diagram is attached below

Answer:

a)  W_{Fg}= 12500 Nm

b)  W_{T_1}= - 6339.3Nm

c)  W_{T_2}= - 3662.8Nm

Explanation:

From the question we are told that:

Mass m=255kg

Distance d=4m

Generally the equation for Work done is mathematically given by

W=F*d

For F_g

W_{Fg}=2500 x 5.3

W_{Fg}= 12500 Nm

For T_1

W_{T_1}= - {1830 sin(60) x 4}

W_{T_1}= - 6339.3Nm

For T_2

W_{T_2}= - {1295  sin(45) x 4}

W_{T_2}= - 3662.8Nm

6 0
3 years ago
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