AMU Medical AMU Solved Paper-1998

  • question_answer
    A ball is thrown with a kinetic energy E at an angle of\[45{}^\circ \]with the horizontal in the earths gravitational field. The change in its potential energy at the highest point of its flight with respect to the starting point will be

    A)  \[+\frac{E}{\sqrt{2}}\]

    B)  \[+\frac{E}{2}\]

    C)  \[-\frac{E}{\sqrt{2}}\]

    D)  \[-\frac{E}{2}\]

    Correct Answer: B

    Solution :

    : At starting point, potential energy = 0 Maximum height attained by projectile\[=\frac{{{u}^{2}}{{\sin }^{2}}\theta }{2g}\] \[\therefore \]\[h=\frac{{{u}^{2}}{{\sin }^{2}}45{}^\circ }{2g}\] or \[h=\frac{{{u}^{2}}}{4g}\] \[\therefore \]Potential energy gained\[=mgh\] \[PE=\frac{m{{u}^{2}}}{4}\] \[PE=\frac{1}{2}\times \frac{1}{2}m{{u}^{2}}=\frac{1}{2}\times E\] or PE gained\[=E/2\].


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