J & K CET Engineering J and K - CET Engineering Solved Paper-2003

  • question_answer
    A particle is vibrating in simple harmonic motion with an amplitude of\[4\text{ }cm\]. 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, \[\omega \] the angular velocity, m the mass. Potential energy is \[U=\frac{1}{2}m{{y}^{2}}{{\omega }^{2}}\] where y is displacement. Given,       \[U=\frac{1}{2}E\] \[\therefore \] \[\frac{1}{2}m{{y}^{2}}{{\omega }^{2}}=\frac{1}{2}\left( \frac{1}{2}m{{a}^{2}}{{\omega }^{2}} \right)\] \[\Rightarrow \] \[{{y}^{2}}=\frac{{{a}^{2}}}{2}=\frac{{{4}^{2}}}{2}=8\] \[\Rightarrow \] \[y=2\sqrt{2}cm\]


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