# Solving the Slinky Wave Problem: HELP!

• andkand97
In summary, the slinky is stretched to 8.2 meters and then one end is plucked sending a transverse pulse. The pulse's travel time there AND back is 8.2-3=5.2 seconds.
andkand97

## Homework Statement

A slinky with natural length of 3.00 meters, mass of 0.750 kg, and spring constant 18.0 N/m is stretched out along a floor, each end held by a seated person. The final length is 8.2 m. One end is plucked sending a transverse pulse. Find the pulse's travel time there AND back.

## Homework Equations

I've been stuck on this problem for hours. It is driving me insane. I don't understand how to find the speed if I don't know the amplitude. Is it the natural length of 3 meters? Even then I still get the wrong answer.

## The Attempt at a Solution

I've tried finding the solution multiple ways but still don't get the right answer. One method was using k = Ftension/x (8.2 m). Then putting that into v=squared root of F/(mass/length). Then used the velocity = wavelength * frequency to solve for frequency, took the inverse and multiplied by two.

Last edited:
andkand97 said:
The find length is 8.2 m
What is that supposed to say?
andkand97 said:
k = Ftension/x (8.2 m). Then putting that into v=squared root of F/(mass/length)
That looks right, except I'm not sure that 8.2m is the right length to be using. Depends on your answer to my first question.

haruspex said:
What is that supposed to say?

That looks right, except I'm not sure that 8.2m is the right length to be using. Depends on your answer to my first question.
Oh sorry. It's supposed to say the final length is 8.2 meters. As in the slinky is stretched to 8.2 m.

andkand97 said:
Oh sorry. It's supposed to say the final length is 8.2 meters. As in the slinky is stretched to 8.2 m.
OK, so how are you calculating the tension?

haruspex said:
OK, so how are you calculating the tension?
Well I have the spring constant and I have the distance it is stretched (8.2 m) so I do 18N/m = F/8.2m and solve for F. Is this not right? Or am I supposed to use the natural length instead?

andkand97 said:
the distance it is stretched (8.2 m)
That's not the distance it is stretched (by).

Oh...crap. So I subtract the natural length of 3 m from that then use it to find the tension, right?

andkand97 said:
Oh...crap. So I subtract the natural length of 3 m from that then use it to find the tension, right?
Yes. (But I think what you did gives the speed for ;longitudinal waves.)

How would I find the speed of a transverse wave?

andkand97 said:
How would I find the speed of a transverse wave?
Sorry, I've confused you. I mean that using the extension (8.2-3) gives the transverse wave speed, but using the total length (as you did initially) gives the longitudinal speed.

Oh okay. I finally got the right answer! Thank you so much I've been working on this since yesterday. Really appreciate it!

## What is the Slinky Wave Problem?

The Slinky Wave Problem is a physics phenomenon where a slinky, when dropped from a height, does not fall straight to the ground but instead creates a wave-like motion as it falls.

## Why is it important to solve the Slinky Wave Problem?

The Slinky Wave Problem is important because it helps us understand the principles of wave motion and how energy is transferred. It also has practical applications in engineering and the study of vibrations.

## What factors affect the Slinky Wave Problem?

The main factors that affect the Slinky Wave Problem are the height from which the slinky is dropped, the tension and elasticity of the slinky, and the force of gravity.

## How can the Slinky Wave Problem be solved?

The Slinky Wave Problem can be solved by using mathematical equations and principles of wave motion to model and predict the behavior of the slinky. Experimentation and observation can also help in understanding the problem.

## What are the real-life applications of the Slinky Wave Problem?

The Slinky Wave Problem has real-life applications in various fields such as structural engineering, seismology, and the study of sound and light waves. It also has practical uses in toys and entertainment.

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