Question

You're standing on a sidewalk when a bus pulls up to the curb. as the driver stops the bus, the brakes squeal loudly. a few people get on, and the bus pulls away from the curb. as the bus accelerates, the engine labors into gear and exhaust fumes spew out the back. the high-pitched squeal of the brakes was caused by _____ sound waves, and the equally loud but low-pitched roar of the engine was caused by _____ sound waves.

a. low-amplitude; high-amplitude
b. high-frequency; low-frequency
c. low-frequency; high-frequency
d. high-amplitude; low-amplitude

Answer 1

The squeal of the brakes is caused by high-frequency sound waves, and the low-pitched roar of the engine is caused by low-frequency sound waves, making option b the correct answer.

Step-by-step explanation:

The high-pitched squeal of the brakes you hear as a bus pulls up is caused by high-frequency sound waves, and the low-pitched roar of the engine as the bus accelerates is caused by low-frequency sound waves. The correct option is b. high-frequency; low-frequency.

High-frequency sounds correspond to sounds with a higher pitch, which is the case with the brake's squeal. Conversely, a roar from an engine is a low-pitched sound, which indicates that the sound waves are of low frequency. Amplitude refers to the loudness of the sound, not the pitch, so options involving amplitude (a and d) are incorrect.