JEE Main & Advanced AIEEE Solved Paper-2003

  • question_answer
    A particle performing uniform circular motion has angular momentum L. If its angular frequency is doubled and its kinetic energy halved, then the new angular momentum is     AIEEE  Solved  Paper-2003

    A) \[\frac{L}{4}\]                   

    B)       2L                           

    C) 4L                           

    D) \[\frac{L}{2}\]

    Correct Answer: A

    Solution :

                   Angular momentum                     \[L=\operatorname{l}\omega \]                                               ... (i) Kinetic energy \[K=\frac{1}{2}l{{\omega }^{2}}=\frac{1}{2}L\omega \]         [from Eq. (i)] \[\therefore \]      \[L=\frac{2K}{\omega }\] Now, the new angular momentum                     \[L'=\frac{2\left( \frac{K}{2} \right)}{2\omega }\]  \[\left( \because K'=\frac{K}{2}and\omega '=2\omega  \right)\] \[\Rightarrow \]   \[L'=\frac{L}{4}\]


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