Easy MCQ +4 / -1 PYQ · JEE Mains 2021

A particle starts executing simple harmonic motion (SHM) of amplitude 'a' and total energy E. At any instant, its kinetic energy is ${{3E} \over 4}$ then its displacement 'y' is given by :

  1. A y = a
  2. B $y = {a \over {\sqrt 2 }}$
  3. C $y = {{a\sqrt 3 } \over 2}$
  4. D $y = {a \over 2}$ Correct answer

Solution

$E = {1 \over 2}K{a^2}$<br><br>${{3E} \over 4} = {1 \over 2}K({a^2} - {y^2})$<br><br>$\Rightarrow$ ${3 \over 4} \times {1 \over 2}K{a^2} = {1 \over 2}K({a^2} - {y^2})$<br><br>$\Rightarrow$ ${y^2} = {a^2} - {{3{a^2}} \over 4}$<br><br>$\Rightarrow$ $y = {a \over 2}$

About this question

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

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