a sound wave traveling downward with a speed of about 4,000 m/s suddenly slows to 1,500 m/s not far below…

a sound wave traveling downward with a speed of about 4,000 m/s suddenly slows to 1,500 m/s not far below the earth’s surface.\nwhat has the sound wave most likely encountered?\n○ a different kind of rock\n○ an underground lake\n○ an open cavity\n○ a pile of dinosaur bones

a sound wave traveling downward with a speed of about 4,000 m/s suddenly slows to 1,500 m/s not far below the earth’s surface.\nwhat has the sound wave most likely encountered?\n○ a different kind of rock\n○ an underground lake\n○ an open cavity\n○ a pile of dinosaur bones

Answer

Brief Explanations:

Sound waves travel at different speeds through different mediums. The speed of sound is generally faster in solids than in liquids and gases. Rocks are solids with varying densities and compositions that can affect sound - wave speed. Water in an underground lake is a liquid, and sound travels slower in liquids compared to most rocks. An open cavity is a gas - filled space (air), and sound travels even slower in gases. Dinosaur bones are less likely to be a common encounter and also do not typically cause such a significant speed change as a change in rock type or encountering a liquid. Since the sound wave slows down significantly, it is most likely that it has entered a medium with lower density like a liquid or gas. An underground lake is the most reasonable option among the choices as it is a common subsurface feature that can cause a significant drop in sound - wave speed.

Answer:

an underground lake