Well, Harry, what you said is not necessarily true the way you said it.
But we know what you mean, and what you meant to say is true.
The Doppler effect is observed if there is relative radial motion
between an object and an observer <em><u>AND</u></em> if the object happens
to be putting out sound or light in the observer's direction.
It will take 21s for yhe alligator to crawl that distance. Reported answer contains 2 Significant Figures.
Answer:we can calculate the answer by the following formula;
Explanation: