RAJASTHAN ­ PET Rajasthan PET Solved Paper-2002

  • question_answer
    Two equal drops of water with a velocity v is falling in air. If both drops are mixed, then velocity will be

    A)  \[2v\]                

    B)  \[\sqrt{2v}\]

    C)  \[{{2}^{2/3}}v\]

    D)  \[\frac{v}{\sqrt{2}}\]

    Correct Answer: C

    Solution :

     \[\frac{4}{3}\pi {{R}^{3}}=2.\frac{4}{3}\pi {{r}^{3}}\] \[R=r{{(2)}^{1/3}}\] \[v\propto {{r}^{2}}\] \[\therefore \] \[\frac{{{v}_{R}}}{{{v}_{r}}}=\frac{{{R}^{2}}}{{{r}^{2}}}\] Or \[\frac{{{v}_{R}}}{v}=\frac{{{r}^{2}}{{(2)}^{2/3}}}{{{r}^{2}}}\] \[{{v}_{R}}={{2}^{2/3}}v\]


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