# Two cars X and Y

Question:

Two cars $\mathrm{X}$ and $\mathrm{Y}$ are approaching each other with velocities $36 \mathrm{~km} / \mathrm{h}$ and $72 \mathrm{~km} / \mathrm{h}$ respectively. The frequency of a whistle sound as emitted by a passenger in car X, heard by the passenger in car $\mathrm{Y}$ is $1320 \mathrm{~Hz}$. If the velocity of sound in air is $340 \mathrm{~m} / \mathrm{s}$, the actual frequency of the whistle sound produced is ........ Hz.

Solution:

$\mathrm{V}_{\mathrm{x}}=36 \mathrm{~km} / \mathrm{hr}=10 \mathrm{~m} / \mathrm{s}$

$\mathrm{V}_{\mathrm{y}}=72 \mathrm{~km} / \mathrm{hr}=20 \mathrm{~m} / \mathrm{s}$

by doppler's effect

$\mathrm{F}^{\prime}=\mathrm{F}_{0}\left(\frac{\mathrm{V} \pm \mathrm{V}_{0}}{\mathrm{~V} \pm \mathrm{V}_{\mathrm{s}}}\right)$

$1320=\mathrm{F}_{0}\left(\frac{340+20}{340-10}\right) \Rightarrow \mathrm{F}_{0}=1210 \mathrm{~Hz}$
The text passage contains a physics problem involving the Doppler effect, with a question about the actual frequency of a whistle sound and a detailed solution provided.
single_question_with_answer
Given a text passage, determine:
    1. If it contains a mathematical question (including word problems or calculations)
    2. If an answer to that mathematical question is provided in the text

First, describe the content structure you found in 1-2 sentences.

Then provide your analysis in the following format:
TYPE: <one of the following values>
- NO_QUESTION
- SINGLE_QUESTION
- SINGLE_QUESTION_WITH_ANSWER
- MULTIPLE_QUESTIONS
- MULTIPLE_QUESTIONS_WITH_ANSWERS
system
# Two cars X and Y

Question:

Two cars $\mathrm{X}$ and $\mathrm{Y}$ are approaching each other with velocities $36 \mathrm{~km} / \mathrm{h}$ and $72 \mathrm{~km} / \mathrm{h}$ respectively. The frequency of a whistle sound as emitted by a passenger in car X, heard by the passenger in car $\mathrm{Y}$ is $1320 \mathrm{~Hz}$. If the velocity of sound in air is $340 \mathrm{~m} / \mathrm{s}$, the actual frequency of the whistle sound produced is ........ Hz.

Solution:

$\mathrm{V}_{\mathrm{x}}=36 \mathrm{~km} / \mathrm{hr}=10 \mathrm{~m} / \mathrm{s}$

$\mathrm{V}_{\mathrm{y}}=72 \mathrm{~km} / \mathrm{hr}=20 \mathrm{~m} / \mathrm{s}$

by doppler's effect

$\mathrm{F}^{\prime}=\mathrm{F}_{0}\left(\frac{\mathrm{V} \pm \mathrm{V}_{0}}{\mathrm{~V} \pm \mathrm{V}_{\mathrm{s}}}\right)$

$1320=\mathrm{F}_{0}\left(\frac{340+20}{340-10}\right) \Rightarrow \mathrm{F}_{0}=1210 \mathrm{~Hz}$
user
The text passage contains a physics problem involving the Doppler effect, with a question about the actual frequency of a whistle sound and a detailed solution provided.

TYPE: SINGLE_QUESTION_WITH_ANSWER