Avehicle traveling away from an observer has a malfunctioning horn that sounds continuously.
if the vehicle travels with a constant positive acceleration away from the observer, which of the following represents the magnitude of the change in frequency experienced by the observer over time?

a. δf is constant over time
b. δf increases linearly over time
c. δf increases exponentially over time
d. δf decreases linearly over time

30) B; To analyze this question, recall the equation for Doppler, Δf/f = v/c. This demonstrates that the change in frequency is directly proportional to the relative velocity. If the acceleration is constant, the velocity is changing at a constant rate, so anything directly proportional to that must be changing at a constant rate. Because no squares or roots are involved, it must be linear, not exponential, making B the best answer.

Explanation:

bacteria that live on the ocean floor are sustained by phytoplankton. phytoplankton, microscopic marine photosynthetic organisms, have a vastly significant role to play not only in the marine food web of which they’re part of, but also on a more global scale. despite their infinitely small size in comparison to other marine organisms, these tiny creatures occupy an immensely important ecological niche: they are the foundation of the marine food web, and as primary producers, play key roles in supporting all other organisms in the marine environment, as well as in the regulation of the earth’s climate through the sequestration of carbon, oxygen production, and other related processes. phytoplankton account for roughly half of all global primary productivity; therefore, their significance extends far beyond the marine environment alone. there is an intriguing sense of irony in the realization that these tiny living beings that often live out their existence unnoticed and undetected by the rest of the world, have such a far-reaching impact on the lives of virtually all other living organisms on the planet, particularly on those in the marine environment. the world that we have become accustomed to has been and is continuously shaped by the workings of these miniscule yet vital “plants of the sea”.

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