Physics

Physics

Problem

(Mass–spring system under general initial conditions) a. (i) Define amplitude and phase constant for the linear simple harmonic motion of a particle attached to an ideal spring. State the physical significance of each term. b. (ii) A particle executing SHM has an initial displacement x0x_{0} and initial velocity v0v_{0} at t=0t=0. Explain qualitatively, without using any numerical values, why knowledge of both x0x_{0} and v0v_{0} is sufficient to fix the amplitude and the phase constant uniquely. c. (iii) Using suitable reasoning, identify the value(s) of the phase constant that correspond to the following special initial situations: (a) the particle is released from one extreme position, (b) the particle passes through the mean position moving in the positive xx–direction, (c) the particle is momentarily at rest at the mean position.
Intuitive explanation

When a mass bounces on a spring, its motion is completely determined by two things: where it starts and how fast it's moving at that moment. The key insight is that any oscillation can be built from a combination of two independent modes—one that depends on initial position and one that depends on initial velocity. By writing the solution as x(t)=Acos⁡(ωt+ϕ)x(t) = A\cos(\omega t + \phi), you're really asking: what amplitude and phase angle make this formula match your specific starting conditions? Use those two initial conditions to solve for those two unknowns.

Intuitive explanation

When a mass bounces on a spring, its motion is completely determined by two things: where it starts and how fast it's moving at that moment. The key insight is that any oscillation can be built from a combination of two independent modes—one that depends on initial position and one that depends on initial velocity. By writing the solution as x(t)=Acos⁡(ωt+ϕ)x(t) = A\cos(\omega t + \phi), you're really asking: what amplitude and phase angle make this formula match your specific starting conditions? Use those two initial conditions to solve for those two unknowns.

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