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JEE Main & Advanced Sample Paper JEE Main Sample Paper-31

  • question_answer
    A police car moving at \[22\,m/s\] chases a motorcyclist. The police man sounds his horn at\[176\,Hz\], while both of them move towards a stationary siren of frequency \[165\,Hz\]. Calculate the speed of the motorcycle, if it is given that motor cyclist does not observe any beats: Police car   Motor cycle   Stationary siren

    A) \[22\,m/s\] 

    B)                    \[33\,m/s\]

    C)  \[11\,\,m/\sec \]            

    D) zero

    Correct Answer: A

    Solution :

    No beats are observed by motorcyclist, so apparent frequency observed by him must be equal. \[{{f}_{1}}={{f}_{2}}\] \[176\left( \frac{330-v}{330-22} \right)=165\left( \frac{330+v}{330} \right)\] on solving\[V=22\,\,m/s\]


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