Easy MCQ +4 / -1 PYQ · JEE Mains 2023

The maximum potential energy of a block executing simple harmonic motion is $25 \mathrm{~J}$. A is amplitude of oscillation. At $\mathrm{A / 2}$, the kinetic energy of the block is

  1. A 9.75 J
  2. B 37.5 J
  3. C 18.75 J Correct answer
  4. D 12.5 J

Solution

$\mathrm{U}_{\max }=\frac{1}{2} \mathrm{~m} \omega^{2} \mathrm{~A}^{2}=25 \mathrm{~J}$ <br/><br/>$\mathrm{KE}$ at $\frac{\mathrm{A}}{2}=\frac{1}{2} m v_{1}^{2}=\frac{1}{2} m \omega^{2}\left(A^{2}-\frac{A^{2}}{4}\right)$ <br/><br/>$=\frac{1}{2} \mathrm{~m} \omega^{2} \frac{3 \mathrm{~A}^{2}}{4}=\frac{3}{4}\left(\frac{1}{2} \mathrm{~m} \omega^{2} \mathrm{~A}^{2}\right)$ <br/><br/>$\mathrm{KE}=\frac{3}{4} \times 25=18.75 \mathrm{~J}$

About this question

Subject: Physics · Chapter: Oscillations · Topic: Simple Harmonic Motion

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