JEE Main & Advanced Physics Work, Energy, Power & Collision / कार्य, ऊर्जा और शक्ति Question Bank Critical Thinking

  • question_answer
    A particle of mass m is moving in a horizontal circle of radius r under a centripetal force equal to \[-K/{{r}^{2}}\], where K is a constant. The total energy of the particle is          [IIT 1977]

    A)             \[\frac{K}{2r}\]          

    B)             \[-\frac{K}{2r}\]

    C)             \[-\frac{K}{r}\]           

    D)             \[\frac{K}{r}\]

    Correct Answer: B

    Solution :

                    Here \[\frac{m{{v}^{2}}}{r}=\frac{K}{{{r}^{2}}}\] \ K.E.\[=\frac{1}{2}m{{v}^{2}}=\frac{K}{2r}\]             \[U=-\int_{\infty }^{r}{F.dr}=-\int_{\infty }^{r}{\left( -\frac{K}{{{r}^{2}}} \right)}\,dr=-\frac{K}{r}\]             Total energy \[E=\text{K}\text{.E}\text{.}+\text{P}\text{.E}\text{.}=\frac{K}{2r}-\frac{K}{r}=-\frac{K}{2r}\]


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