JEE Main & Advanced Physics Work, Energy, Power & Collision / कार्य, ऊर्जा और शक्ति Question Bank Self Evaluation Test - Work, Energy and Power

  • question_answer
    Two blocks of masses m and M are joined with an ideal spring of spring constant k and kept on a rough surface as shown. The spring is initially unstretched and the coefficient of friction between the blocks and the horizontal surface is u. What should be the maximum speed of the block of mass M such that the smaller block does not move?

    A) \[\mu g\sqrt{\frac{Mm}{\left( M+m \right)k}}\]

    B) \[\mu g\sqrt{\frac{\left( M+m \right)k}{Mm}}\]

    C) \[\mu g\sqrt{\frac{\left( 2M+m \right)m}{kM}}\]

    D) None of these

    Correct Answer: C

    Solution :

    [c] For the smaller block to move \[k{{x}_{0}}=\mu mg\]and from work energy theorem \[-\mu Mg{{x}_{0}}-\frac{1}{2}k\,{{x}_{0}}^{2}=-\frac{1}{2}M\,\,{{v}^{2}}_{0}\] \[+\mu Mg\left( \frac{\mu mg}{k} \right)+\frac{1}{2}k{{\left( \frac{\mu mg}{k} \right)}^{2}}=\frac{1}{2}M\,\,{{v}^{2}}\] \[v=\mu m\sqrt{\frac{\left( 2M+m \right)m}{kM}}\]


You need to login to perform this action.
You will be redirected in 3 sec spinner