JEE Main & Advanced Sample Paper JEE Main Sample Paper-29

  • question_answer
    A rod is projected such that it is rotating about its c.m. during its flight. Its angular velocity:

    A) during ascent decreases

    B) during decent decreases

    C) during ascent increases

    D) remain same

    Correct Answer: D

    Solution :

    Force mg is acting at c.m. Hence torque about c.m. zero Hence \[\frac{dy}{dx}=\frac{2}{3}\,{{x}^{-1/3}}+\frac{1}{3}\,{{x}^{-2/3}}\,=\frac{\left( 2{{x}^{1/3}}+1 \right)}{3{{x}^{2}}3}\] constant Hence \[\frac{dy}{dx}=0;\,\,{{x}^{1/3}}\,=\frac{-1}{2}\] remain same


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