Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • Engineering
  • The frequency of a car horn encountered a change from 400 Hz to 500 Hz. When the car approaches a vertical wall. If the speed of sound is 330 m/s. Then the speed of car is ______ km/h.Option: 1 132Option: 2 -Option: 3 -

The frequency of a car horn encountered a change from 400 Hz to 500 Hz. When the car approaches a vertical wall. If the speed of sound is 330 m/s. Then the speed of car is ______ km/h.
 

Answers (1)

best_answer

Frequency of a car horn cncounter change from 400 Hz to 500 Hz

\begin{aligned} &f_{\text {app }}=500 \mathrm{~Hz}\\ &f=400 H z \\ &f_{\text {app }}=f\left(\frac{V+V_{s}}{V-V_{s}}\right) \\ &\frac{5}{4}=\frac{\left(330+V_{s}\right)}{\left(330-V_{s}\right)} \end{aligned}

\begin{gathered} 5 \times 330-5 V_{s}=4 \times 330+4 V_{s} \\ 330=5 V_{s}+4 V_{s}=9 V_{s} \end{gathered}

V_{s}=\frac{330}{9} \mathrm{m} / \mathrm{s}

\begin{aligned} V_{s}=\frac{330}{9} \frac{\mathrm{m}}{\mathrm{s}}=\frac{330}{9} \times \frac{18}{\mathrm{5}} \\ \left(\because 1 \frac{\mathrm{km}}{\mathrm{h}}=\frac{5}{18} \frac{\mathrm{m}}{\mathrm{s}}\right)\\ =132\left(\frac{\mathrm{km}}{ \mathrm{hr}}\right) . \end{aligned}

Posted by

vishal kumar

View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE

Similar Questions

Trending Articles/News

anam-khan

JEE Main 2025: 2nd attempt? Mistakes to avoid, tips to improve score, percentile
anam-khan

JEE Main 2025: What to expect on exam day? Section-wise paper pattern, marking scheme, last-minute tips
anam-khan

JEE Main 2025 Live: NTA JEE session 2 exams from tomorrow; updates on admit card, exam pattern, passing marks

Latest Question