Cheat sheet · Class 11 · CBSE · Science Physics

Oscillations cheat sheet

The whole chapter on one page: key formulas, facts and the points to remember, for quick revision before a test.

CBSE Class 11 · Physics

Cheat sheet

Chapter 13Oscillations

SHM: restoring force ∝ −displacement.

1. SHM Equations

x=Acos⁡(ωt+ϕ)x = A\cos(\omega t + \phi)
v=ωA2−x2v = \omega\sqrt{A^2 - x^2}a=−ω2xa = -\omega^2 x
  • vmax=Aωv_{max} = A\omega at mean position; amax=Aω2a_{max} = A\omega^2 at extremes.

2. Time Period

T=2πmkT = 2\pi\sqrt{\dfrac{m}{k}} (spring)
T=2πlgT = 2\pi\sqrt{\dfrac{l}{g}} (pendulum)

Simple pendulum formula holds for small angles.

3. Energy in SHM

K=12k(A2−x2)K = \tfrac12 k(A^2 - x^2)U=12kx2U = \tfrac12 kx^2E=12kA2E = \tfrac12 kA^2

Total energy constant; KE max at mean, PE max at extremes.

4. Springs

  • Series: 1k=1k1+1k2\dfrac1k = \dfrac1{k_1} + \dfrac1{k_2}.
  • Parallel: k=k1+k2k = k_1 + k_2.
  • Cutting a spring in half doubles k.

5. Key Points

  • Periodic ≠ always SHM.
  • ω = 2π/T = 2πν.
  • Velocity leads displacement by π/2.
  • Pendulum period independent of mass.

Remember: a = −ω²x | T for spring & pendulum | E = ½kA²

Oscillations: questions and notes

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