How does the doppler effect explain the sound you hear when a race car comes toward and then passes a camera? a) the pitch is higher as it approaches and then becomes lower the moment it passes. b) the pitch is lower as it approaches and then becomes higher the moment it passes. c) the sound is louder as it approaches and then becomes softer the moment it passes. d) the sound is softer as it approaches and then becomes louder the moment it passes.

The answer is A) The pitch is higher as it approaches and then becomes lower the moment it passes.

The correct option is A.

Explanation:

Doppler effect is a phenomenon in which there is a increase or decrease in the frequency when there is a relative motion between the source and the listener.

When the source and the observer are moving away from other then the frequency decreases in this case.

When the source and the observer are moving towards each other then the frequency increases in this case.

When a race car comes toward and then it passes. you will hear higher frequency of car when it approaches towards to you.  When it passes then you will hear a lower frequency of the sound as you are back of the racing car. The pitch depends on the frequency. Higher the frequency, higher will be the pitch and vice versa.

Therefore, the pitch is higher as it approaches and then becomes lower the moment it passes.

Khi truyền tải điện năng có công suất không đổi đi xa với đường dây tải điện một pha có điện trở r xác định để công suất hao phí trên đường dây tải điện giảm đi 100 lần thì ở nơi truyền đi phải dùng một máy biến áp lí tưởng có tỉ số vòng dây giữa cuộn thứ cấp và cuộn sơ cấp là

please translate in English

xD