Math Problem Statement

The position of an object undergoing simple harmonic motion is given by 𝑑(𝑑) = 5π‘π‘œπ‘ (6𝑑 + where d is given in meters and t is measured in seconds. Positive Ο€ 6 ) values of d indicate towards the right and negative values towards the left. a. Find the earliest time at which the object is farthest to the right from d=0, its equilibrium position. b. Find the frequency of the motion in Hz. c. Find the maximum velocity of the object

Solution

The equation of simple harmonic motion is given by:

d(t)=5cos⁑(6t+Ο€6)d(t) = 5\cos\left(6t + \frac{\pi}{6}\right)

where:

  • d(t)d(t) is the displacement in meters.
  • tt is the time in seconds.
  • The amplitude is 55 meters.
  • The angular frequency is 6 rad/s6 \, \text{rad/s}.

We will answer each part in turn.


a. Finding the earliest time when the object is farthest to the right:

The object is farthest to the right when d(t)d(t) is at its maximum positive value, i.e., d(t)=5 md(t) = 5 \, \text{m}.

This happens when the cosine term reaches its maximum value, which is cos⁑(θ)=1\cos(\theta) = 1. So, we want:

cos⁑(6t+Ο€6)=1\cos\left(6t + \frac{\pi}{6}\right) = 1

The cosine function is equal to 1 when the angle ΞΈ=2nΟ€\theta = 2n\pi, where nn is an integer. So, set the argument of the cosine equal to 2nΟ€2n\pi:

6t+Ο€6=2nΟ€6t + \frac{\pi}{6} = 2n\pi

To find the earliest positive time, use n=0n = 0:

6t+Ο€6=06t + \frac{\pi}{6} = 0

Solve for tt:

6t=βˆ’Ο€66t = -\frac{\pi}{6}

t=βˆ’Ο€36t = -\frac{\pi}{36}

Since time cannot be negative, we'll move to the next solution by setting n=1n = 1:

6t+Ο€6=2Ο€6t + \frac{\pi}{6} = 2\pi

Solve for tt:

6t=2Ο€βˆ’Ο€66t = 2\pi - \frac{\pi}{6}

6t=12Ο€6βˆ’Ο€6=11Ο€66t = \frac{12\pi}{6} - \frac{\pi}{6} = \frac{11\pi}{6}

t=11Ο€36t = \frac{11\pi}{36}

Thus, the earliest time tt when the object is farthest to the right is:

t=11Ο€36 secondst = \frac{11\pi}{36} \, \text{seconds}


b. Finding the frequency of the motion:

The angular frequency Ο‰\omega is given by:

Ο‰=6 rad/s\omega = 6 \, \text{rad/s}

The relationship between angular frequency and regular frequency ff is:

Ο‰=2Ο€f\omega = 2\pi f

Solve for ff:

f=Ο‰2Ο€=62Ο€=3π Hzf = \frac{\omega}{2\pi} = \frac{6}{2\pi} = \frac{3}{\pi} \, \text{Hz}

Thus, the frequency of the motion is:

f=3π Hzβ‰ˆ0.955 Hzf = \frac{3}{\pi} \, \text{Hz} \approx 0.955 \, \text{Hz}


c. Finding the maximum velocity of the object:

The maximum velocity occurs when the object is at the equilibrium position, which is when the cosine term goes through 0 and the sine term reaches its maximum.

The velocity v(t)v(t) is the derivative of d(t)d(t):

v(t)=ddt(5cos⁑(6t+Ο€6))v(t) = \frac{d}{dt}\left(5\cos\left(6t + \frac{\pi}{6}\right)\right)

Using the chain rule:

v(t)=βˆ’5β‹…6sin⁑(6t+Ο€6)v(t) = -5 \cdot 6 \sin\left(6t + \frac{\pi}{6}\right)

v(t)=βˆ’30sin⁑(6t+Ο€6)v(t) = -30 \sin\left(6t + \frac{\pi}{6}\right)

The maximum value of sin⁑(θ)\sin(\theta) is 1, so the maximum velocity is:

vmax=30 m/sv_{\text{max}} = 30 \, \text{m/s}


Summary of Results:

a. The earliest time at which the object is farthest to the right is t=11Ο€36 secondst = \frac{11\pi}{36} \, \text{seconds}.
b. The frequency of the motion is 3Ο€β‰ˆ0.955 Hz\frac{3}{\pi} \approx 0.955 \, \text{Hz}.
c. The maximum velocity of the object is 30 m/s30 \, \text{m/s}.


Would you like further details on any step or part of this solution?

Here are 5 related questions you can explore:

  1. How would you find the period of the motion?
  2. How does the amplitude affect the energy in simple harmonic motion?
  3. What is the acceleration of the object at the equilibrium position?
  4. How would the motion change if the angular frequency doubled?
  5. Can you determine the phase shift of the motion?

Tip: The maximum velocity in simple harmonic motion is always Ο‰A\omega A, where Ο‰\omega is the angular frequency and AA is the amplitude.

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Math Problem Analysis

Mathematical Concepts

Simple Harmonic Motion
Trigonometry
Angular Frequency
Maxima and Minima

Formulas

d(t) = Acos(Ο‰t + Ο†)
Ο‰ = 2Ο€f
v_max = Ο‰A

Theorems

Simple Harmonic Motion Theory
Trigonometric Identities
Derivatives of Trigonometric Functions

Suitable Grade Level

Grades 11-12