BCECE Medical BCECE Medical Solved Papers-2010

  • question_answer
    A spring is held compressed so that its stored energy is 2.4 J. Its ends are in contact with masses 1 g and 48 g placed on a frictionless table. When the spring is released, the heavier mass will acquire a speed of

    A)  \[\frac{2.4}{49}m{{s}^{-1}}\]

    B)  \[\frac{2.4\times 48}{49}m{{s}^{-1}}\]

    C)  \[\frac{{{10}^{3}}}{7}cm{{s}^{-1}}\]

    D)  \[\frac{{{10}^{6}}}{7}cm{{s}^{-1}}\]

    Correct Answer: C

    Solution :

    \[\frac{1}{2}{{m}_{1}}v_{1}^{2}+\frac{1}{2}{{m}_{2}}v_{2}^{2}=2.4\] or            \[{{m}_{1}}v_{1}^{2}+{{m}_{2}}v_{2}^{2}=4.8\] ... (i) now,      \[{{m}_{1}}{{v}_{1}}={{m}_{2}}{{v}_{2}}\] or            \[{{v}_{1}}=48\,{{v}_{2}}\] Using Eq. (i) \[\frac{1}{1000}\,{{(48{{v}_{2}})}^{2}}+\frac{48}{1000}v_{2}^{2}=4.8\] or            \[\frac{48}{1000}(49\,v_{2}^{2})=4.8\] \[\therefore \] \[{{v}_{2}}=\frac{10}{7}m/s=\frac{{{10}^{2}}}{7}cm/s\]


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