Vibration and Frequency Questions

In summary, the first conversation discusses a bungee cord with a mass of 75 g and an equilibrium length of 1.20 m. When stretched to 1.80 m and vibrated at 20 Hz, it produces a standing wave with two antinodes. The linear density is found to be 0.0626 kg/m, but the solution is unclear.The second conversation talks about earthquakes and their seismic waves, which can be longitudinal (P waves) or transverse (S waves). These waves travel at different speeds, with P waves traveling at 8000 m/s and S waves at 4500 m/s. A seismograph records these waves from a distant earthquake. The equations for this problem are
  • #1
Draco
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Homework Statement


A 75 g bungee cord has an equilibrium length of 1.20 m. The cord is stretched to a length of 1.80 m, then vibrated at 20 Hz. This produces a standing wave with two antinodes.

Homework Equations


Linear Density = m/L

The Attempt at a Solution


So far I've only found the linear density to be 0.0626kg/m. I'm stuck after this and have no clue on where to start next.

Homework Statement


Earthquakes are essentially sound waves traveling through the earth. They are called seismic waves. Because the Earth is solid, it can support both longitudinal and transverse seismic waves. These travel at different speeds. The speed of longitudinal waves, called P waves, is 8000m/s . Transverse waves, called S waves, travel at a slower 4500m/s . A seismograph records the two waves from a distant earthquake.

Homework Equations



Not sure.

The Attempt at a Solution


I'm not exactly sure on how to start this. This topic is very new to me. Can someone get me started?
 
Last edited:
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  • #2
So what I did for this question is, attempt to plug in values for 'm' so, for example

390 = m v/2L
390 = 1 343/2L

and find length that way,
it turned out that 390 represents the 3rd modal where (m = 3). Velocity is of course 343 m/s because sound will travel thorugh the tube which is open-open.
 
  • #3
oh yeah, i got that question just after I posted. Thanks for explaining a different method though. I used a different way to find the length of the tube.
 
  • #4
um can anyone fill me in on these two questions?
 

FAQ: Vibration and Frequency Questions

What is vibration and frequency?

Vibration is the rapid back-and-forth motion of an object or particle, while frequency is the number of vibrations per unit of time. In simpler terms, vibration is a physical movement, and frequency is a measure of how often that movement occurs.

What causes vibrations?

Vibrations can be caused by various factors such as mechanical forces, electrical signals, and sound waves. Some common examples include a guitar string vibrating when plucked, a phone vibrating when receiving a notification, and an earthquake causing the ground to shake.

How are vibration and frequency related?

Vibration and frequency are directly proportional. This means that as the frequency increases, so does the amplitude or intensity of the vibration. In other words, the higher the frequency, the more rapid and intense the back-and-forth motion becomes.

What is resonance and how does it relate to vibration and frequency?

Resonance is a phenomenon that occurs when the frequency of an external force is equal to the natural frequency of an object. This causes the object to vibrate with a larger amplitude, which can result in structural damage or even failure. For example, a glass can shatter if a singer's voice matches its natural frequency.

How is vibration and frequency used in science and technology?

Vibration and frequency have various applications in science and technology. In engineering, they are used to design and test structures and machines for durability. In medicine, they are used in diagnostic imaging techniques such as ultrasound. In music, they are used to produce different notes and pitches. In communication, they are used to transmit and receive signals. Overall, understanding vibration and frequency is essential in many fields of science and technology.

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