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rusak2 [61]
3 years ago
10

An old mining tunnel disappears into a hillside. You would like to know how long the tunnel is, but it's too dangerous to go ins

ide. Recalling your recent physics class, you decide to try setting up standing-wave resonances inside the tunnel. Using your subsonic amplifier and loudspeaker, you find resonances at 5.0 and 6.4 , and at no frequencies between these. It's rather chilly inside the tunnel, so you estimate the sound speed to be 340 .Based on your measurements, how far is it to the end of the tunnel?
Physics
1 answer:
PilotLPTM [1.2K]3 years ago
4 0

Answer:

121.43 m

Explanation:

Solution

Since standing waves are set up, the expression for the first mode of frequency is f₁ = nv/4L. The next mode of frequency is f₂ = (n + 2)v/4L where L is the length of the tunnel and v the speed of sound. f₁ = 5.0 Hz, f₂ = 6.4 Hz, v = 340 m/s. We now subtract f₂ - f₁ = (n + 2)v/4L - nv/4L = v/2L.

So f₂ - f₁ = v/2L. and L = v/2(f₂ - f₁) = 340/[2× (6.4-5.0)] = 340/2×1.4 = 340/2.8 = 121.43 m

So, it is 121.43 m far to the end of the tunnel.

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Would u rather/ have a penny that duplicates its self every day or win 1 million dollars once
arlik [135]

Answer:

1 million dollars once

Explanation:

Well, both would be nice. In total, you will get more from the million dollars because it takes over 2,739 years to get 1 million dollars worth of pennies.(if you get 1 a day that is)

8 0
3 years ago
a motorcycle accelerates from 15 m/s to 20 m/s over a distance of 50 meters. what is its average acceleration?
devlian [24]
For this, you need the v-squared equation, which is v(final)² = v(initial)² + 2aΔx The averate acceleration is thus a = (v(final)² - v(initial)²) / 2Δx = (20² - 15²) / 2(50) = 175 / 100 = 1.75 m/s² So the average acceleration is 1.75 m/s²
5 0
3 years ago
During a demonstration of the gravitational force on falling objects to her class, Sarah drops an 11 lb. bowling ball from the t
tia_tia [17]

1.A) 4.9 m  

AL2006 Ace

The instant it was dropped, the ball had zero speed.


After falling for 1 second, its speed was 9.8 m/s straight down (gravity).


Its AVERAGE speed for that 1 second was (1/2) (0 + 9.8) = 4.9 m/s.


Falling for 1 second at an average speed of 4.9 m/s, is covered 4.9 meters.


ANYTHING you drop does that, if air resistance doesn't hold it back.


Read more on Brainly.com - brainly.com/question/11776597#readmore

2 idk sorry

5 0
3 years ago
Read 2 more answers
A 0.750kg block is attached to a spring with spring constant 13.5N/m . While the block is sitting at rest, a student hits it wit
vazorg [7]

Answer:

A)A=0.075 m

B)v= 0.21 m/s

Explanation:

Given that

m = 0.75 kg

K= 13.5 N

The natural frequency of the block given as

\omega =\sqrt{\dfrac{K}{m}}

The maximum speed v given as

v=\omega A

A=Amplitude

v=\sqrt{\dfrac{K}{m}}\times A

0.32=\sqrt{\dfrac{13.5}{0.75}}\times A

A=0.075 m

A= 0.75 cm

The speed at distance x

v=\omega \sqrt{A^2-x^2}

v=\sqrt{\dfrac{K}{m}}\times \sqrt{A^2-x^2}

v=\sqrt{\dfrac{13.5}{0.75}}\times \sqrt{0.075^2-(0.075\times 0.75)^2}

v= 0.21 m/s

5 0
3 years ago
PSYCHOLOGY <br> Which of these statements are false ?
nataly862011 [7]

Answer:

The false statement has to be that neruotransmitters are in the spinal cord.

Explanation:

Neruotransmitters are in no was associated with the spinal cord. That is more related to nerves and muscles. Neurotransmitters are in the Phasma Membrane acording to sciencedirect.com.

4 0
2 years ago
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