The variation of potential energy of a harmonic oscillator is as shown in the figure. Then, find the spring…

The variation of potential energy of a harmonic oscillator is as shown in the figure. Then, find the spring constant.
  1. \(1 \times 10^2 \mathrm{Nm}^{-1}\)
  2. \(150 \mathrm{Nm}^{-1}\)
  3. \(0.667 \times 10^2 \mathrm{Nm}^{-1}\)
  4. \(3 \times 10^2 \mathrm{Nm}^{-1}\)

Solution

According to figure, when \(y=20 \mathrm{~mm}\) \(=2 \times 10^{-2} \mathrm{~m}\) then \(U_{\max }=0.04 \mathrm{~J}=4 \times 10^{-2} \mathrm{~J}\)
When \(y=0\) then \(U_{\min }=0.01 \mathrm{~J}=1 \times 10^{-2} \mathrm{~J}\) \(\therefore\) The change in potential energy, \(\begin{array}{ll} & U_{\max }-U_{\min }=\frac{1}{2} K y^2 \\ \Rightarrow & 4 \times 10^{-2}-1 \times 10^{-2}=\frac{1}{2} K \times\left(2 \times 10^{-2}\right)^2 \\ \Rightarrow & 3 \times 10^{-2}=K \times 2 \times 10^{-4} \\ \Rightarrow & \quad K=\frac{3 \times 10^{-2}}{2 \times 10^{-4}}=1.5 \times 10^2=150 \mathrm{Nm}^{-1} \end{array}\)

Asked in: AP EAMCET 2020 (17 Sep Shift 2)

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