JEE Advanced – Simple Harmonic Motion (SHM)

Previous-Year Level Questions with Solved Answers

Concept → Method → Calculation → Insight


Q1. Energy Equality in SHM

A particle performs SHM with amplitude A. At what displacement will its kinetic energy equal potential energy?

Solution:

Total Energy:
E = ½ kA²

At displacement x:
PE = ½ kx²
KE = ½ k(A² − x²)

Equating KE = PE:

½kx² = ½k(A² − x²)
2x² = A²
x = A / √2

Answer: ± A / √2

JEE Insight: Energy questions avoid time and phase completely.


Q2. Time from Mean to A/2

Time taken by a particle in SHM to move from x = 0 to x = A/2?

Solution:

x = A sin(ωt)

sin(ωt) = 1/2 ⇒ ωt = π/6

t = π / (6ω)

Since T = 2π / ω:

t = T / 12

Answer: T / 12

JEE Trick: Always convert time answers into fractions of T.


Q3. Maximum Acceleration

In SHM, at what position is acceleration maximum?

Solution:

a = −ω²x

|a| is maximum when |x| is maximum → x = ±A

Answer: At extreme positions

Examiner Trap: Many students wrongly answer “mean position”.


Q4. Effect of Doubling Amplitude

If amplitude of SHM is doubled, what happens to maximum speed?

Solution:

vmax = ωA

If A → 2A ⇒ vmax → 2vmax

Answer: Maximum speed doubles


Q5. Frequency & Acceleration Relation

Two SHMs have same amplitude but frequencies f₁ and f₂. Find ratio of maximum accelerations.

Solution:

amax = ω²A = (2πf)²A

a₁ / a₂ = (f₁ / f₂)²

Answer: (f₁ / f₂)²


Q6. Parallel Spring SHM

A mass m is attached to two identical springs (k) in parallel. Find time period.

Solution:

keq = k + k = 2k

T = 2π √(m / 2k)

Answer: 2π√(m / 2k)


Q7. Phase Difference for Cancellation

At what phase difference do two SHMs cancel completely?

Answer: 180° (π radians)


Q8. Velocity at Mean Position

Is velocity always maximum at mean position?

  • Yes – in ideal SHM
  • No – if damping or external forces exist

Examiner Thinking: Check if student assumes ideal conditions.


How JEE Toppers Approach SHM

  • Decide energy / time / phase first
  • Avoid blind formula writing
  • Convert answers into T, A, ω form
  • Use symmetry in motion
  • Never mix linear & angular terms

JEE Advanced SHM – Solved PYQ Module Completed

📚 IIT–JEE Physics Complete Library

Concept Mastery • PYQs • Strategy • Revision
One-stop structured learning hub


🔹 Simple Harmonic Motion (SHM) — Core Series

Coverage: Concepts → PYQs → Advanced Thinking → Exam Readiness


🔹 Simple Harmonic Motion (SHM) — Extended Series (30–56)

These pages are placed separately for continuity & reference.

30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56


🔹 Supporting & Mega Libraries


✔ Library logically bifurcated • ✔ All links preserved • ✔ Student-first design

No comments:

Post a Comment

  📘 IIT–JEE Physics Complete Master Library (Class XI & XII) Concepts • Problems • Advanced Applications • Thinking Skill...