Train Whistle Echo: Calculating Distance & Temperature Effects

AI Thread Summary
The discussion revolves around calculating the distance to a reflecting surface based on the time it takes for a train engineer to hear an echo from a stationary railroad whistle. The engineer hears the echo 4.0 seconds later, leading to a calculated distance of 686 meters using the speed of sound at 343 m/s. Participants also discuss how an increase in air temperature affects the speed of sound, noting that higher temperatures result in faster sound transmission. A reference link is provided to support this claim about temperature's effect on sound speed. Understanding these principles is essential for accurately solving similar problems in physics.
Xoloti
Messages
3
Reaction score
0

Homework Statement


a)a stationary railroad whistle is sounded. An echo is heard 4.0 seconds later by a train's engineer. If the speed of sound is 343 m/s, how far away is the reflecting surface?
b) If the temperature of the air increased, how would this change your answer?

Homework Equations


d=rt
x=xt/2

The Attempt at a Solution


I got part a right. x=(343*4)/2 =686 because the sound has to travel twice
I do not know part b
 
Physics news on Phys.org
Xoloti said:

Homework Statement


a)a stationary railroad whistle is sounded. An echo is heard 4.0 seconds later by a train's engineer. If the speed of sound is 343 m/s, how far away is the reflecting surface?
b) If the temperature of the air increased, how would this change your answer?

Homework Equations


d=rt
x=xt/2

The Attempt at a Solution


I got part a right. x=(343*4)/2 =686 because the sound has to travel twice
I do not know part b
Welcome to the PF.

How does the speed of sound in air change with a change in air temperature? :smile:
 
berkeman said:
Welcome to the PF.

How does the speed of sound in air change with a change in air temperature? :smile:
Higher the temperature faster the speed of sound. Thanks!
 
Xoloti said:
Higher the temperature faster the speed of sound. Thanks!
Really? That may be true, but it's counter-intuitive for me. Do you have a link to a reference that says that? :smile:
 

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »

Thread 'Rolling without slipping on a curved surface'

Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
View full post »

Similar threads

Hearing the Train Whistle Frequency: Calculating fs
Replies
6
Views
5K
Doppler Effect: Train A and B Whistle Frequency Calculation
Replies
1
Views
2K
Doppler Effect: Velocity of a train
Replies
4
Views
2K
When does a sound echo not disturb its listener
Replies
4
Views
2K
How Does Wind Affect the Doppler Effect in a Two-Train Scenario?
Replies
1
Views
2K
Solve Physics Echo Problem: Air Echo Returns 1.33s Later
Replies
3
Views
2K
Calculate Additional Time for Echo in Air to Return | Physics Problem
Replies
10
Views
5K
Solve for Echo Time in Saltwater and Air - Physics Problem
Replies
5
Views
2K
How Does the Doppler Effect Alter Perceived Train Whistle Frequencies?
Replies
18
Views
8K
Calculating Distance Traveled by a Honking Car and Echo
Replies
18
Views
2K

Hot Threads

Recent Insights

Back
Top