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A force of 12 N is required to stretch a spring 4 m. A mass of 1 kg is attached to the spring and the spring is submerged in a medium creating a damping force numerically equal to four times the velocity. The spring is strecthed 1 m past equilibrium and released from rest. Find the equation of motion of the spring as a function of time.

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Final answer:

The equation of motion for a spring with a mass attached to it is x(t) = A cos(ωt + φ), where A is the amplitude, ω is the angular frequency, and φ is the phase constant. With a force constant of 12 N/m and a mass of 1 kg, the angular frequency is 2√3. The equation of motion for the spring as a function of time is x(t) = A cos(2√3 t).

Step-by-step explanation:

The equation of motion for a mass attached to a spring undergoing simple harmonic motion is given by the equation:

x(t) = A cos(ωt + φ)

Where:

  • x(t) is the displacement of the mass from its equilibrium position at time t
  • A is the amplitude of the oscillation
  • ω is the angular frequency and is given by ω = sqrt(k/m), where k is the force constant of the spring and m is the mass attached to the spring
  • φ is the phase constant

In this case, the force constant is 12 N/m (as stated in the question) and the mass is 1 kg. Therefore, the angular frequency is ω = sqrt(12/1) = sqrt(12) = 2√3. The displacement from equilibrium at time t is given by:

x(t) = A cos(2√3 t + φ)

To find the equation of motion as a function of time, we need to determine the phase constant φ. At t = 0, the mass is stretched 1 m past equilibrium. Plugging in these values into the equation, we have:

1 = A cos(0 + φ)

Since cos(0 + φ) = cos(φ), we have:

1 = A cos(φ)

From this equation, we can determine that φ = 0 (since cos(0) = 1). Therefore, the equation of motion for the spring as a function of time is:

x(t) = A cos(2√3 t)

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