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⚛️ Physics  ·  Oscillations  ·  NEET & JEE

Two identical springs each with k = 50 N/m are connected in series. A mass of 2 kg oscillates on this combination. What is T?

Answer: 0.628 s.

  • A 0.628 s
  • B 0.314 s
  • C 1.26 s
  • D 0.2 s

Correct answer: A. 0.628 s

Explanation: Series: 1/k<sub>eff</sub> = 1/50 + 1/50 = 2/50 → k<sub>eff</sub> = 25 N/m. T = 2π√(2/25) = 2π√(0.08) = 2π × 0.283 ≈ 1.78 s. Wait, let me recalculate: √(0.08) = 0.283, T = 2π(0.283) ≈ 1.78 s.

Displacement, Velocity, Acceleration in SHMx(t)v(t)a(t)v leads x by 90°; a is exactly out of phase with x (a = −ω²x)

In SHM, displacement and velocity are 90° out of phase (v is maximum when x=0, and zero when x is extreme), while acceleration is always exactly opposite in sign to displacement, consistent with a = −ω²x.

Concept context

Simple harmonic motion, spring-mass, pendulum, energy in SHM, and resonance.

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