J & K CET Medical J & K - CET Medical Solved Paper-2003

  • question_answer
    A particle is vibrating in simple harmonic motion with an amplitude of 4 cm. At what displacement from the equilibrium position is its energy half potential and half-kinetic?

    A) \[2\sqrt{2}cm\]                                

    B) \[\sqrt{2}cm\]

    C)  2 cm                                     

    D)  1 cm

    Correct Answer: A

    Solution :

                    In simple harmonic motion total energy is \[E=\frac{1}{2}m{{a}^{2}}{{\omega }^{2}}\] where a is amplitude, co the angular velocity, m the mass. Potential energy is                 \[U=\frac{1}{2}m{{y}^{2}}{{\omega }^{2}}\] where y is displacement. Given,       \[U=\frac{1}{2}E\] \[\therefore \]  \[\frac{1}{2}m{{y}^{2}}{{\omega }^{2}}=\frac{1}{2}\left( \frac{1}{2}m{{a}^{2}}{{\omega }^{2}} \right)\] \[\Rightarrow \]               \[{{y}^{2}}=\frac{{{a}^{2}}}{2}=\frac{{{4}^{2}}}{2}=8\] \[\Rightarrow \]               \[y=2\sqrt{2}cm\]


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