Sound Wave quesions (Grade 11 Physics)

[pkevin91]

Homework Statement

1. "When filling your car with gasoline, in the last few seconds before filling the tank, a noise with a rising pitch comes from the tank. Explain"
2. "Liona Boyd, a famous Canadian guitarist, tunes her guitar's A string with a 440 Hz tuning fork. Beats are heard at a frequency of 4 Hz. To give herself more information, Mrs. Boyd wraps a piece of masking tape around one of the tuning fork tines and continues tuning. This time, a beat frequency of 5 Hz is heard. Is more information required to find the specific frequency of the string? What are the possible frequencies of the string? In each case, what should Ms. Boyd do to tune the string?"

Homework Equations

1. The teacher told me to think about the standing waves in air columns.
2. No idea :P...

The Attempt at a Solution

 

[member 553083]

1. The noise with a rising pitch is likely caused by the growth and subsequent collapse of standing waves in the air column inside the tank. As the tank is filled, the pressure of gas increases, leading to an increase in frequency of the standing waves. This results in the noise becoming higher pitched as the tank is filled. 2. More information is required to find the specific frequency of the string. Possible frequencies of the string are 440 Hz, 445 Hz, and 450 Hz. For each case, Ms. Boyd should use the tuning fork to compare the frequency of the string to the frequency of the tuning fork. She should then adjust the tension on the string and repeat the process until she achieves a frequency match.