Simple harmonic motion (SHM) — identify the correct statement Which of the following statements about a particle executing simple harmonic motion (SHM) is correct? Choose the most accurate definition or property.

Difficulty: Easy

Correct Answer: The periodic time of a particle in SHM is the time taken for one complete oscillation.

Explanation:


Introduction / Context:
This question checks your conceptual understanding of simple harmonic motion (SHM) — a foundational topic in engineering mechanics and physics. Knowing which definitions and properties are correct helps when analyzing springs, pendulums, and vibration problems.



Given Data / Assumptions:

  • A particle performs SHM about a mean (equilibrium) position.
  • Standard SHM relations apply: x = r sin(ωt + φ), v = ωr cos(ωt + φ), a = −ω^2 x.
  • Angular frequency ω and amplitude r are constants for the motion considered.


Concept / Approach:
The periodic time (or period) T is the time taken to complete one full oscillation and return to the same dynamic state. For ideal SHM, T = 2π / ω. Velocity and acceleration vary sinusoidally: velocity is maximum at the mean position and zero at extremes; acceleration is zero at the mean and maximum in magnitude at extremes.



Step-by-Step Solution:

Identify the precise definition: “periodic time” is time for one complete cycle.Check dependence on ω: T = 2π / ω, so T is inversely proportional to ω, not directly proportional.At the mean position, x = 0 → v = ωr (maximum), a = 0.At extremes, v = 0 and |a| = ω^2 r (maximum).


Verification / Alternative check:
Using energy: total energy E = (1/2) k r^2 is constant; kinetic energy is maximum at the mean where speed is maximum, consistent with the kinematics above.



Why Other Options Are Wrong:

  • Directly proportional to ω: Incorrect; T ∝ 1/ω.
  • Velocity zero at mean: Opposite; velocity is maximum at mean.
  • Acceleration maximum at mean: Acceleration is zero at mean and maximal at extremes.
  • Kinetic energy maximum at extremes: It is maximum at mean, not extremes.


Common Pitfalls:
Confusing where velocity versus acceleration are maximum; mixing up period and frequency relations.



Final Answer:
The periodic time of a particle in SHM is the time taken for one complete oscillation.


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