Math Problem Statement

A spring of relaxed length of 0.23m and stiffness of 17N/m stands vertically on top of a shelf that allows it to oscillate both above and below the shelf. A block of mass 0.090kg is attached to the top of the spring. You pull the block upward stretching the spring until its length is now 0.29m, hold the block at rest for a moment and then release it. What is the y component of the block relative to of the shelf after a since time step 0.06s after you release the block. The +y direction is vertically upward the origin is at the top of the she,f and the magnitude of acceleration due to gravity g=10.

Solution

Let's break this down step-by-step.

Problem Overview:

  • Spring constant (k): 17 N/m
  • Relaxed length of spring (L₀): 0.23 m
  • Mass of the block (m): 0.090 kg
  • Initial stretched length of spring (L₁): 0.29 m
  • Gravity (g): 10 m/s²
  • Time (t): 0.06 s
  • Origin (y = 0): Top of the shelf, with the +y direction being upward.

Steps to Solve:

  1. Determine the force at the equilibrium position: When the block is at rest after being stretched, the force on the block is the spring force and the gravitational force. At equilibrium, these forces balance.

    The spring force is given by Hooke's Law: Fspring=kΔyF_{\text{spring}} = k \Delta y where Δy=L1L0=0.29m0.23m=0.06m\Delta y = L_1 - L_0 = 0.29 \, \text{m} - 0.23 \, \text{m} = 0.06 \, \text{m}.

    So, Fspring=17×0.06=1.02NF_{\text{spring}} = 17 \times 0.06 = 1.02 \, \text{N} The gravitational force is: Fgravity=mg=0.090kg×10m/s2=0.90NF_{\text{gravity}} = m \cdot g = 0.090 \, \text{kg} \times 10 \, \text{m/s}^2 = 0.90 \, \text{N}

    The spring force is upwards, and gravity is downwards. The net force at equilibrium is zero, as the spring force exactly balances gravity.

  2. Set up the equation for oscillation: After the release, the block will undergo simple harmonic motion (SHM) about the equilibrium position. The displacement y(t)y(t) from the equilibrium position follows the SHM equation:

    y(t)=Acos(ωt+ϕ)y(t) = A \cos(\omega t + \phi) where:

    • AA is the amplitude of oscillation,
    • ω\omega is the angular frequency,
    • ϕ\phi is the phase constant.

    To find AA, we note that the block was initially pulled to a length of 0.29 m, and when released, it oscillates from this position. Therefore, the amplitude is the initial displacement from equilibrium: A=0.29m0.23m=0.06mA = 0.29 \, \text{m} - 0.23 \, \text{m} = 0.06 \, \text{m}

  3. Find the angular frequency ω\omega: The angular frequency for SHM is: ω=km\omega = \sqrt{\frac{k}{m}} Substituting values: ω=170.090188.8913.75rad/s\omega = \sqrt{\frac{17}{0.090}} \approx \sqrt{188.89} \approx 13.75 \, \text{rad/s}

  4. Determine the phase constant ϕ\phi: Since the block is released from rest at the maximum displacement, the cosine function starts at its maximum value, so ϕ=0\phi = 0.

  5. Find the displacement at t=0.06t = 0.06 s: Using the equation for SHM: y(t)=Acos(ωt)y(t) = A \cos(\omega t) Substituting the known values: y(0.06)=0.06cos(13.75×0.06)y(0.06) = 0.06 \cos(13.75 \times 0.06) y(0.06)=0.06cos(0.825)y(0.06) = 0.06 \cos(0.825) Using cos(0.825)0.670\cos(0.825) \approx 0.670: y(0.06)0.06×0.670=0.0402my(0.06) \approx 0.06 \times 0.670 = 0.0402 \, \text{m}

Thus, after 0.06 seconds, the displacement of the block relative to the shelf is approximately 0.0402 m above the equilibrium position (so above the shelf).


Final Answer:

The yy-component of the block’s position relative to the shelf at t=0.06t = 0.06 s is approximately 0.0402 m.

Would you like a more detailed breakdown of any step, or do you have any questions about the calculation?


Related Questions:

  1. How does the spring constant kk affect the oscillation period?
  2. What happens to the amplitude of oscillation if the spring is stretched more or less?
  3. How would the frequency change if the block had a different mass?
  4. How would the phase change if the block were released from a different position?
  5. What is the period of the oscillation of this system?

Tip:

When dealing with oscillations, always keep track of the equilibrium position (where forces are balanced) and use it as a reference point for your calculations!

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Math Problem Analysis

Mathematical Concepts

Simple Harmonic Motion
Spring Force
Oscillations
Trigonometry

Formulas

Hooke's Law: F_spring = k * Δy
Angular Frequency: ω = √(k/m)
SHM Equation: y(t) = A * cos(ω * t + φ)

Theorems

Hooke's Law
Simple Harmonic Motion

Suitable Grade Level

Grades 10-12