A student measures the speed of sound using the echo method. She stands 170 m from a wall and claps repeatedly, timing 10 echoes. The total time for 10 echo...
Question 1 Report
A student measures the speed of sound using the echo method. She stands 170 m from a wall and claps repeatedly, timing 10 echoes. The total time for 10 echoes is 10.0 s.
What speed of sound does she calculate?
Answer Details
In the echo method, the sound travels from the student to the wall and back again. The total distance for one echo is therefore \( 2 \times 170 = 340 \, \text{m} \).
Since the student times 10 echoes and the total time is 10.0 s, the time for one echo is:
\[ t = \frac{10.0}{10} = 1.0 \, \text{s} \]
The speed of sound is then:
\[ v = \frac{d}{t} = \frac{340}{1.0} = 340 \, \text{m/s} \]
A common error is forgetting that the sound must travel to the wall and back, which would give half the correct answer (170 m/s). Another error is dividing the total distance by the total time without first finding the time per echo, which would give 17 m/s.
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