Question

1. at how many miles an hour will sound travel through air that is 68 degrees?
2. a plane traveling at the ______ speed of mach 3 is going how fast relative to the speed of sound?
3. most of the objects in our daily lives travel at _________ speeds.
4. what four things do sound waves have in common with other waves?
5. sound is constantly being what?
6. what causes an echo?
7. what makes it possible to focus sound using curves surfaces?

Explanation:

1. The speed of sound in dry air at 68°F (20°C) is approximately 767 miles per hour.
2. Mach number is the ratio of the speed of an object to the speed of sound. A plane at Mach 3 is going 3 times the speed of sound.
3. Most objects in daily - life travel at sub - sonic speeds (slower than the speed of sound).
4. Sound waves, like other waves, have amplitude (related to loudness), frequency (related to pitch), wavelength, and speed.
5. Sound is constantly being produced, reflected, absorbed, and transmitted.
6. An echo is caused by the reflection of sound waves off a surface.
7. The reflection and focusing properties of curved surfaces (similar to how curved mirrors work for light) make it possible to focus sound.

Answer:

1. Approximately 767 miles per hour
2. 3 times the speed of sound
3. Sub - sonic
4. Amplitude, frequency, wavelength, speed
5. Produced, reflected, absorbed, transmitted
6. Reflection of sound waves off a surface
7. Reflection and focusing properties of curved surfaces