GED Science Practice

What is the "Sound barrier" in aerodynamics?

1. A barrier preventing entry into sonic booms

2. The limit to how loud a sound can be

3. The increase in aerodynamic drag as an airplane approaches the speed of sound

4. A device that blocks all sound waves

The correct answer is: The increase in aerodynamic drag as an airplane approaches the speed of sound

The term "sound barrier" refers to the phenomenon known as a sonic boom, which occurs when an aircraft travels through the air at speeds faster than the speed of sound. As an aircraft approaches the speed of sound, the air around it begins to compress and form a shock wave, creating a loud noise. This can be disruptive and potentially damaging to structures on the ground. Therefore, aircraft designers must consider the impact of the "sound barrier" on their aircraft and take measures to minimize the effects, such as by designing sleek and streamlined shapes. Option A is incorrect because the sound barrier is not a physical barrier, but rather a phenomenon. Option B is incorrect because the sound barrier is not a measure of loudness, but rather a limit of speed. Option D is incorrect because a sound barrier does not actually block sound waves, but rather results in a specific sound (a sonic boom) when a certain speed is reached.