This tag is for non-relativistic material strings, such as, e.g., a guitar string. PLEASE DO NOT USE THIS TAG for relativistic strings and string theory.

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2answers
34 views

String wrapping around a motionless cylinder

A particle is connected to the end of a thin, weightless string, which has its other end connected to the cylinder, in such a way that motion of the particle causes the string to wrap around the ...
1
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1answer
43 views

Analysis of motion of a body moving on a string?

I was wondering about something I observed yesterday. To give some background, one of my hobbies is slacklining. This is essentially like tight-rope walking but with a one inch piece of (in this case ...
5
votes
5answers
8k views

Why can't a rope be pulled completely straight?

I have found several discussions on how to calculate the sag of rope that is tied off at two points (like a tightrope), and I understand it to a certain extent. What I can't wrap my head around is how ...
2
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0answers
30 views

Distribution forces

I've got two trees and between them is a rope. When someone about 100kg sits at the center of the rope, what are the forces on both parts of rope (to the left-hand side from the person and right-hand ...
2
votes
0answers
34 views

Tensions in a rope [duplicate]

If two tensions are acting on a rope such that they are equal (each is 10 N) and opposite (180 degrees) then what will be the total tension in the rope? I cant seem to figure out if these two will ...
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3answers
3k views

Young's Modulus and Vibrating String Harmonics

I was wondering how Young's Modulus effects the resonant harmonics of a vibrating (string instrument) string. I know that the string's fundamental frequency is $$\frac{1}2 \times \text{Length} \times ...
1
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2answers
35 views

Waves on a guitar string

Can there be traveling waves on a string that is attached at both ends (like a guitar string), or does such a configuration allow only standing waves ?
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3answers
68 views

Tension on a string

A string is attached at both extremities and put under tension $T_0$ at rest. We know that if we pull the string upwards from the middle, the tension will increase. But why is it that, admittedly, ...
2
votes
1answer
272 views

Wave on a guitar string, differential equation

The mechanical energy of an element of the string is : $$dE(x,t) = \frac{1}{2}\left[T_0\left(\frac{\partial y}{\partial x}\right)^2 + \mu\left(\frac{\partial y}{\partial t}\right)^2\right]dx$$ Where ...
0
votes
1answer
157 views

Solve hanging rope question by using Lagrangian density [closed]

for this one, I can only do the first(a) $$V_{total}=\frac{mg}{l} \int_{x_0}^{d-x_0}{y(x)\sqrt{1+(\frac{dy(x)}{dx})^2}}dx$$ and have no idea about others.
4
votes
3answers
1k views

Tension of rope. Different Answers?

The tension of a rope in a tug of war with unequal forces is equal to the least force on the rope. Am I right? (If group A pulls the wire with 20 newton leftwards and the group B pulls with 30 newton. ...
1
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2answers
178 views

Can we define tension in a string as the reactive force produced in a string being pulled at both ends?

In my textbook, the definition of tension was given that Tension is the reactive force which exists when string is being stretched at its both end. After it there was a case given that to calculate ...
2
votes
1answer
31 views

Wave hitting a boundary with a mass on it?

If we have a transverse wave that is infinite in the $-x$ direction and terminate by a mass $m$, that is allowed to move in the $y$ direction at $x=0$ as shown in the diagram below: I think we can ...
0
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4answers
398 views

Does increasing the tension on a string also increase the density?

Consider a string under tension, for example, a string on a guitar. When a guitar string is plucked, it vibrates at a certain frequency. When the tension on the string is increased by twisting the ...
1
vote
2answers
72 views

Derive Equation for Position of Antinode

I'm not sure what to do for this. The equation for standing waves on a string is given by: $$ y=2A\sin{(kx)}\cos{(\omega t)} $$ Use this equation to derive an equation for the position of the ...
1
vote
1answer
53 views

Can two bodies of different mass attached at ends of string passed over a frictionless pulley produce equal tension on both sides?

In my textbook there is given a case that to calculate acceleration and tension produced in string when string is attached at it's ends with two bodies of masses such that $m1>m2$ and the tension ...
1
vote
1answer
68 views

When do we assume that a rope has different tensions in different places?

Working a problem with 2 pulleys and masses in class this week the professor at one point assumed that the tension on the two sides of a pulley would be different. Every other time we've done a ...
0
votes
1answer
69 views
1
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0answers
26 views

Non-linearity of a guitar pickup

I basically understand induction and why a pickup generates a signal. (From: http://www.brighthubengineering.com/consumer-appliances-electronics/64277-the-physics-behind-the-electric-guitar/) What ...
0
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2answers
1k views

How did tension developed in a string when two equal and opposite forces are applied on the same body?

As per Newton's 3rd law every action has an equal and opposite reaction, but both of these forces are on different bodies under consideration Now when a single body (say rope in this case) is ...
2
votes
3answers
107 views

Why do these standing waves appear to be traveling?

Take a look at this video: https://www.youtube.com/watch?v=TKF6nFzpHBU You would expect guitar strings to produce standing waves, and in fact, the upper, thickest string does often produce long, ...
0
votes
1answer
64 views

Calculation of tension in a loop with force acting outwards

I'm having a few problems with understanding how to calculate tension in a loop. If I have a circular loop, and some force is applied uniformly radially outwards in such a way that the force acting ...
0
votes
2answers
248 views

When is tension constant in a rope?

Suppose we have a massless rope with pulling forces applied at each end. In which scenarios is the tension in the rope constant throughout? For example if there is a knot in the rope the tension is ...
1
vote
2answers
131 views

Which Force would help find the mass?

Two masses, A and B, are connected to a rope. A constant upward force 86.0N is applied to box A. Starting from rest, box B descends 12.1m in 4.70s . The tension in the rope connecting the two boxes is ...
1
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0answers
27 views

Unusual waves and one of its parameter

I'm messing up with this java app on the web about waves on a string and i'm really curious about something. The java app is the following : ...
22
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7answers
7k views

Why Won't a Tight Cable Ever Be Fully Straight?

I posted this picture of someone on a zipline on Facebook. One of my friends saw it and asked this question, so he could try to calculate the speed at which someone on the zipline would be going ...
0
votes
2answers
72 views

Finding the one-dimensional wave equation the vibrating string

It's a relatively simple problem and I've been able to solve it in a different way before, but the current book I'm learning from left me with some questions: After a few idealizations we get the ...
0
votes
0answers
44 views

Question on a variant of Atwood machine with strings unwinding in one side

The figure is standard Atwood machine except that for the right object string tension acts on the left side of the object, and strings unwind from the object. No slip condition on a rolling ...
2
votes
2answers
188 views

Nature of tension in a massless rope [duplicate]

I'm faced with a conceptual problem, where I am supposed to describe the motions of the following system (two masses on each end of a totally inelastic rope hanged on a pulley): I understand that ...
3
votes
1answer
83 views

Moments of vibrating string

I have to calculate first 10 moments for vibrating string with damping, but I don't know how to do it. I read about moments and in definition they mention linear system $$x'=Ax+Bu, \qquad y=Cx$$ with ...
2
votes
1answer
47 views

Beads flying out of flask

There is a popular youtube video of some metal beads being thrown out of a flask, literally hovering out of the container My question is how detailed a physical explanation of this phenomenon we ...
1
vote
0answers
30 views

Energy in a string [closed]

A nylon string of length L = 50 cm and under a tension of T = 70 N is plucked with an amplitude of 5 mm. What is the energy in the string? Please give me the relationship between energy of the ...
0
votes
1answer
75 views

Determining the decay constant for a damped wave [closed]

My question is short and simple. If a damped, travelling wave (say on a string) could be described as $y\left( x,t\right) =Ae^{-\gamma x}\sin \left( kx-\omega t\right)$ how could/would one ...
0
votes
1answer
324 views

Massive ropes and tension

Consider the diagram bellow, a massive string hanging in equilibrium My question is this: Can we take any 2 random point on the rope, say A and B and then use $\sum F=0$ on the rope between them: ...
0
votes
1answer
812 views

How does friction and mass of the string influence the tension force?

According to my book, "tension is the reaction of a rope when it is stressed". Then it also said when the string is massless, tension is same everywhere. However in a,let, pulley-rope system,when ...
-2
votes
1answer
64 views

Resonant Frequency & Opera Singers [closed]

Would it be possible under math of strings to note the frequency of each string vibrations? And in doing so, in hand with using the technique opera singers use to shatter glass with their voice, would ...
3
votes
0answers
679 views

Shape of a string/chain/cable/rope/wire?

The height of a string in a gravitational field in 2-dimensions is bounded by $h(x_0)=h(x_l)=0$ (nails in the wall) and also $\int_0^l ds= l$. ($h(0)=h(l)=0$, if you take $h$ as a function of arc ...
2
votes
1answer
144 views

Finding the Shape of a Hanging Massive Wire

This came from a physics wave book. I have a static, massive wire on the x-axis, with a y-displacement due to a force per unit length $F_y$. I start with the equation $F_y = ...
0
votes
0answers
520 views

Tension on a string pulled by unequal forces

Suppose two cases where masses are attached to massless, inextensible strings. In the first case a body which has a weight of 20 Newtons(downwards) is attached to a string which is acted upon ...
1
vote
1answer
165 views

Tension in an Atwoods machine conceptual?

Assuming $T_1$ is the force that acts on box $1$ and $T_2$ is the force that acts on box $2$. Exactly what causes the Tension? Why does $T_1 = T_2$? The problem is we are told to memorize that ...
1
vote
1answer
91 views

Ratio of energy of normal modes of string

Suppose there's a wave on a string represented by fourier series: $$y(x,t) = \sum_{n=0}^{\infty} (-1)^n \frac{1}{2n+1} \sin(nx)\cos(nct)$$ I know the energy is $\propto y^2 n^2$, where $y$ is the ...
-1
votes
1answer
53 views

String vibration

In many textbooks an illustration of a vibrating string at a fundamental mode shown (and wikipedia) shown like this http://en.wikipedia.org/wiki/File:Standing_waves_on_a_string.gif). However if you ...
6
votes
5answers
734 views

Why do harmonics occur when you pluck a string?

When you energise a taut string, the following resonant modes of vibration occur: Plotting on the frequency domain, you can see their corresponding frequencies: But what is the underlying ...
2
votes
2answers
104 views

Where does a string tighten when you pull it?

I have the following setup: The string of negligible mass, causing little friction, is shown in dark blue and is fixed at the red circle. The taut string is shown in light blue (with excess string ...
1
vote
1answer
533 views

How do I recover the 1D wave equation from the Lagrangian?

Consider small displacements, $y(x,t)$, of an element of a string (circled in red and shown below) from equilibrium. The force balance in the vertical direction yields: $$+\uparrow \Sigma F: ...
6
votes
4answers
11k views

Rope tension question

If two ends of a rope are pulled with forces of equal magnitude and opposite direction, the tension at the center of the rope must be zero. True or false? The answer is false. I chose true though and ...
-1
votes
1answer
99 views

Finding the mass of 7cm string [closed]

If a string has $120$ g and length $40$ cm. I found that the linear mass density is given by $$120g/40cm=\ linear\ mass\ density$$ How do I use this to find the mass of a $7$cm of the same kind of ...
0
votes
1answer
81 views

How does a transverse wave propogate in a medium?

I have been told that trasverse wave propogates by the oscillation of medium particles in direction perpendicular to propogation. Consider a wave on a taught string (x-y plane). What is the ...
0
votes
1answer
504 views

Equations of motion for bob-on-a-string — am I missing some terms?

The dynamics of a type of physical system I am currently working on are modeled in most of the literature by replacing the moving parts of that system with an equivalent set of pendulums. Parameters ...
3
votes
1answer
116 views

Work done by vibrating string

figure from http://webusers.physics.illinois.edu/~m-stone5/mma/notes/amaster.pdf The string has fixed ends, a mass per unit length of $\rho$, and is under tension $T$. This source claims that "the ...