Damped harmonic oscillator for a mass hanging from a spring

In summary, the conversation discusses solving a question on dampened harmonic motion using the general solution from the book. The solution involves using complex number solutions and energy equations, and there are different solutions for different cases (underdamped, critical, and overdamped). The question also considers the effect of a hammer blow on the motion and how to incorporate it into the solution. Ultimately, the conversation concludes that the general solution is applicable and the hammer blow only provides initial conditions for fitting the solution.
  • #1
Phantoful
30
3

Homework Statement


g9XAO77.png


Homework Equations


Complex number solutions
z= z0eαt
Energy equations and Q (Quality Factor)

The Attempt at a Solution


For this question, I followed my book's "general solution" for dampened harmonic motions, where z= z0eαt, and then you can solve for α and eventually getting an answer of x=Ae-(ϒ/2)tcos(ω1t+∅) where ω1=sqrt((ω02-(ϒ/2)2)). This is just for the underdampened case and there are other solutions for the critical and overdampened case. However, I don't think these are the answers and I'm not even sure how to interpret these "general solutions". For this question would the case be any different if a v(0) = v0, and the mass is hanging? Should I treat it like a driven harmonic oscillator because of the hammer? This is the first time I'm answering a question like this one.
 

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  • #2
All the hammer blow does is to give you a non-zero initial velocity. Otherwise, just solve the ODE for the prescribed conditions.
 
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  • #3
Phantoful said:

Homework Statement


View attachment 223518

Homework Equations


Complex number solutions
z= z0eαt
Energy equations and Q (Quality Factor)

The Attempt at a Solution


For this question, I followed my book's "general solution" for dampened harmonic motions, where z= z0eαt, and then you can solve for α and eventually getting an answer of x=Ae-(ϒ/2)tcos(ω1t+∅) where ω1=sqrt((ω02-(ϒ/2)2)). This is just for the underdampened case and there are other solutions for the critical and overdampened case. However, I don't think these are the answers and I'm not even sure how to interpret these "general solutions". For this question would the case be any different if a v(0) = v0, and the mass is hanging? Should I treat it like a driven harmonic oscillator because of the hammer? This is the first time I'm answering a question like this one.

The general solution in the book is applicable to your problem. A hanging mass will oscillate about its equilibrium position. x is the deviation from the equilibrium.
Hitting once with the hammer does not mean that the oscillator is driven., It provides the initial conditions you have to fit the general solution to: At t=0 x(0)=0 and v(0)=v0. Determine A and θ for each case.
 
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  • #4
Thank you!
Dr.D said:
All the hammer blow does is to give you a non-zero initial velocity. Otherwise, just solve the ODE for the prescribed conditions.

ehild said:
The general solution in the book is applicable to your problem. A hanging mass will oscillate about its equilibrium position. x is the deviation from the equilibrium.
Hitting once with the hammer does not mean that the oscillator is driven., It provides the initial conditions you have to fit the general solution to: At t=0 x(0)=0 and v(0)=v0. Determine A and θ for each case.
 

1. What is a damped harmonic oscillator?

A damped harmonic oscillator is a system in which a mass is attached to a spring and is subject to damping, or a force that reduces its oscillations over time. This system is commonly used in physics to model real-world phenomena such as the motion of a pendulum or a vibrating object.

2. How does damping affect the behavior of a harmonic oscillator?

Damping reduces the amplitude of the oscillations of a harmonic oscillator over time, causing the system to eventually come to rest. This is in contrast to an undamped harmonic oscillator, which would continue to oscillate indefinitely with the same amplitude.

3. What factors affect the rate of damping in a harmonic oscillator?

The rate of damping in a harmonic oscillator is affected by the strength of the damping force and the natural frequency of the system. The higher the damping force, the faster the system will come to rest. The natural frequency, which is determined by the mass and spring constant, also plays a role in the rate of damping.

4. How is a damped harmonic oscillator different from an undamped harmonic oscillator?

An undamped harmonic oscillator will continue to oscillate with the same amplitude and frequency indefinitely, while a damped harmonic oscillator will eventually come to rest due to the presence of a damping force. Additionally, an undamped harmonic oscillator has a constant amount of energy, while a damped harmonic oscillator loses energy over time.

5. How is a damped harmonic oscillator used in real-world applications?

Damped harmonic oscillators have a variety of real-world applications, including shock absorbers in cars and buildings, vibration control in machinery, and modeling of electrical circuits. They are also commonly used in scientific research to study the effects of damping on systems and to understand more complex phenomena.

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