Question

Difficulty: HardSimple Harmonic Motion

A particle of mass 0.50 kg0.50\text{ kg} executes simple harmonic motion along a straight line. When its displacement from the equilibrium position is 0.06 m0.06\text{ m}, its speed is 0.80 m/s0.80\text{ m/s} and its potential energy is 0.09 J0.09\text{ J}. What is the magnitude of the maximum acceleration of the particle in m/s2\text{m/s}^2?

Answer: 10 m/s^2

Answer

The magnitude of the maximum acceleration of the particle is 10 m/s210\text{ m/s}^2.
Using potential energy Ep=12mω2x2E_p = \frac{1}{2}m\omega^2 x^2, the angular frequency ω\omega is 10 rad/s10\text{ rad/s}. Using v=ωA2x2v = \omega\sqrt{A^2 - x^2}, the amplitude AA is 0.10 m0.10\text{ m}. Substituting these values into amax=ω2Aa_{\max} = \omega^2 A yields 10 m/s210\text{ m/s}^2.

Step-by-Step Solution

1
Find angular frequency ω\omega from potential energy.
ω=10 rad/s\omega = 10\text{ rad/s}
Using potential energy Ep=12mω2x2E_p = \frac{1}{2}m\omega^2 x^2: 0.09=12(0.50)ω2(0.06)2    0.09=0.0009ω2    ω2=100    ω=10 rad/s0.09 = \frac{1}{2}(0.50)\omega^2 (0.06)^2 \implies 0.09 = 0.0009 \omega^2 \implies \omega^2 = 100 \implies \omega = 10\text{ rad/s}.
2
Find amplitude AA from speed.
A=0.10 mA = 0.10\text{ m}
Using speed v=ωA2x2v = \omega\sqrt{A^2 - x^2}: 0.80=10A20.062    0.08=A20.0036    0.0064=A20.0036    A2=0.0100    A=0.10 m0.80 = 10\sqrt{A^2 - 0.06^2} \implies 0.08 = \sqrt{A^2 - 0.0036} \implies 0.0064 = A^2 - 0.0036 \implies A^2 = 0.0100 \implies A = 0.10\text{ m}.
3
Calculate maximum acceleration.
amax=10 m/s2a_{\max} = 10\text{ m/s}^2
Using maximum acceleration formula amax=ω2Aa_{\max} = \omega^2 A: amax=100×0.10=10 m/s2a_{\max} = 100 \times 0.10 = 10\text{ m/s}^2.

Key Concept

Simple Harmonic Motion Energy and Kinematic Relations
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