Questions tagged [string]

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
66 views

Why can't I choose blocks attached with pulley B as a system?

Three blocks of masses m1, m2 and m3 are connected as shown in the figure. All the surfaces are frictionless and the string and pulleys are light. Find the acceleration of the block of mass m1. ...
2
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4answers
91 views

Wave Equation derivation

I'm curious about part of the derivation of the wave equation as is done in all references that I've seen so far (I'm gonna reproduce only the part that's puzzling me). We apply Newton's second law ...
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0answers
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For wave functions $y(x, t)$, how the second order partial differentiation works as second order absolute differentiation?

Ref: http://www.animations.physics.unsw.edu.au/jw/wave_equation_speed.htm As far as we've defined wave as the disturbance caused due to Force obeying Hooke's Law. So, the derivation was started with ...
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2answers
37 views

Force and tension in a pulley

So imagine a pulley (frictionless) with a massless string. On each side are 2 weights 1 of 10 g and 1 of 20g. In the free body force diagrams for the 2nd body we say that $m(g+a)= t$ But shouldn't ...
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0answers
22 views

${}$ A tug of war with different forces at each end of the rope [duplicate]

In tug of wars usually both the teams apply equal force on the rope resulting in the development of tension in the rope which is of the same magnitude as that of the applied force. But, now if one ...
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0answers
34 views

A tug of war with different forces at each end of the rope [closed]

If a man pulls a rope with a force of 150N towards him and the other end of the rope is pulled by a small girl with a force of 50N towards her. Assuming rope to be massless. Find tension in the string....
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0answers
30 views

Tension. Forces [duplicate]

Suppose I pull molecule A of a rope then it also pulls me back by newtons 3rd law. The force that I applied on the rope caused tension in the string , but then what is the effect of the force which ...
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0answers
46 views

Does touching the string at nodal points kill all the overtones or kick the string into a higher energy state? [on hold]

I saw a question about string action where the answer said touching the string at a nodal point kills all the higher overtones in the Fourier series! So standing waves 2, 3, 4,... have only one ...
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1answer
27 views

Newton's laws of motion tension

I am very much confused about tension. I have even Googled my doubts (Also used khan academy) to clear my doubts but even there explanation couldn't satisfy me. PLEASE SOLVE THIS QUERY:- what ...
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0answers
47 views

A tough integration based problem [closed]

A massless rope is tossed over a wooden dowel of radius $r$ in order to lift a heavy object of weight $W$ off the floor. The coefficient of sliding friction between the rope and the dowel is $\mu$. ...
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0answers
19 views

Is the frequency of the vibating string orthogonal to the pitch? [closed]

The frequency of a vibrating string measures transverse wavelengths per second but the pitch is an algebraic measure of geometric distance along the horizontal length of the standing wave. So pitch is ...
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0answers
18 views

Speed of Transverse wave and frequency in sitar wire [closed]

I have a problem to solve though i am not clear on concept. I know, $V = C (T/m)^{1/2}$ Where $C$ is constant, $T$ is tension , $m$ is mass per unit length. Here is the problem A sitar wire in ...
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0answers
19 views

Wave equation, Closed string and string shooter

I have some question about wave equation in "pathological" condition. 1) what is the solution on the wave equation if the string in closed? (ex. a closed string in rotation around his center) I ...
1
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1answer
43 views

About working of tension force

From the past 3-4 days I have been continuously thinking how tension actually works on atomic level. I have even Googled it many times but I was not satisfied with the answers. Can anyone please help ...
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1answer
47 views

Length of Rope in Tug Of War Matter?

I had a question about Tug of War Game, Does the length of the rope really matter, whats the difference between a 50cm rope and a 5meter Rope in Force, Torque And Safety in Tug Of War.
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3answers
37 views

Tension in a string attached to different masses

Does tension in a string remain same even if masses attached to it are of different weights? I have provided a diagram, according to me the tension in string should be different as masses hanging ...
0
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1answer
26 views

Tension about disk

A uniform disk of mass $M = 8.0 \;\mathrm{kg}$ can rotate without friction on a fixed axis. A string is wrapped around its circumference and is attached to a $m = 6.0 \;\mathrm{kg}$ mass. The string ...
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0answers
26 views

Does the Second Law of Thermodynamics imply that a vibrating string tends toward the volumetric shape with the least surface area?

The catenoid formed by revolution of the cosh x function around its axis is the string volumetric in analytic geometry with the least area. The catenoid can be seen topologically as a coherent string-...
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0answers
46 views

If a string had mass in an Atwood machine, would the objects be at rest?

So I understand that the tension produced by a string in an Atwood Machine is constant throughout the string assuming it is ideal, but what if it wasn't? Wouldn't there be a tension gradient, in which ...
1
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1answer
34 views

Why pulley systems give mechanical advantage?

In a system with 2 pulleys, to lift a x kg object y meters I would need half the force that the object exerts due to gravity but pull the rope double the distance, why does this happen this way?
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1answer
42 views

Tension constraint

I have a question about the pulley configuration in the following problem: Why can't we apply the tension constraint $$T_{1a}-T_{2a}-T_{1a}=0?$$ This would imply that $T_{2a}=0$. I know this is ...
13
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6answers
611 views

When a ball on a rope swings in a circle, is there both centripetal force and tension force?

I'm learning about centripetal force and I was shown a scenario where a man was spinning a rope attached to a ball over his head. There's a centripetal acceleration toward the center and therefore a ...
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1answer
35 views

Can you please explain the statement in the David Morin's Classical Mechanics? [duplicate]

For example, in a hanging massless rope, or in a massless rope hanging over a frictionless pulley, the tension must be the same at all points, because otherwise there would be a net force on at ...
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1answer
34 views

Tangential Motion of an Object Attached by a Radial Elastic String [closed]

A toy car travels in a horizontal circle of radius 2a, kept on track by a radial elastic string of unstretched length a. The period of rotation is T. When the car is speeded up the string stretches ...
2
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2answers
60 views

What length can a metal wire (cable) hang vertically?

What length can a cable hang vertically with no additional weight attached to it. I tried figuring this out with 5/8 aircraft cable specs by dividing the rated weight capacity of the cable by the ...
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0answers
45 views

Constrained Motion [closed]

There are two bodies viz. A and B which are placed on a horizontal surface. The free end P is being pulled by a constant force of 1 N. Find the acceleration of free end P? My approach Sign ...
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1answer
52 views

Tension in a string with unequal forces

Let's suppose that there is a massless string. If we apply unequal forces along the rope along a straight line, let's say we apply 60N and 70N forces, then what is the tension in the rope? It would ...
23
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8answers
1k views

Shape of a rotating rope with one free-end [closed]

One end of a uniform rope (with total mass $M$) is fixed on the edge of a cylinder. The cylinder has a radius $R$ and rotates with angular velocity $\omega$. The axis is vertical in a gravitational ...
0
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0answers
55 views

Having some tension about the Tension in Atwood's Machine [closed]

I was thinking about how the tension force is equal in a massless String. While the explanation that the String would accelerate crazy, crazy, crazy fast if there was an actual difference makes sense, ...
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1answer
40 views

Newtonian Mechanics - Pulley block system, finding acceleration [closed]

The question is to find acceleration of the block m1 in the above system (please look at diagram). So I took tension along String 2 to be T and thus Tension along String 1 would be 2T. Acceleration ...
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1answer
47 views

Frequency of longitudinal waves on a string

I recently heard the composer Ellen Fullman on her Long String Instrument, which consists of steel wires of approx. 20 m length played by rubbing/stroking the string longitudinally. Changing the ...
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1answer
52 views

Tension in a string moving in elevator

A lift can move in $x$ axis and also in $y$ axis. A bob of mass m is suspended with inextensible thread inside the ceiling of elevator. Determine tension $T$ in the string when elevator moves in $x$ ...
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0answers
26 views

At what rate is tension released from a plucked string (eg. guitar string)?

Tension in a plucked string (such as a guitar) dictates many of the important changes that occur in the sound of the string over time. eg. It causes a pitch bend, a change in inharmonicity, and ...
1
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0answers
16 views

What is the resultant force acting upward on the point of contact under an elastic deformation?

The situation here is you have an elastic string (or a rubber band) fixed at two ends A and B. A•-------------------------------------------------•B An object is ...
2
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0answers
19 views

String conservation with springs

I was trying to solve this Problem that asked to find the period of small oscillations for this system. To do so I used the fact that for a massless pulley with strings around it, the sum of the ...
0
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1answer
33 views

Tension in a string attached to a spring with deformation at a point

I am trying to calculate the tension in a string in the configuration shown in the diagram below. Here is a verbal description of the setup: The string is fixed at one end with the other end connected ...
1
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1answer
48 views

Dropping a rope in a black hole [duplicate]

If there is a spaceship hovering above a black hole so that it can get away, what would happen if the spaceship connected a rope to itself and dropped the rope in? Could you pull the rope out?
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4answers
51 views

Tension in string due to two opposite forces [duplicate]

If you attach a ideal string to a wall and pull it with force F, there should be a tension T=F in the string. And the string will apply force F on the wall too. But what if there are two persons ...
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1answer
50 views

How does velocity being given to the bob here create tension in the string? [closed]

Based on intuition, the lesser the velocity the bob is initially given, the sooner will the string slack. I don’t understand how the velocity the bob is given initially is related to tension being ...
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4answers
95 views

Newtonian mechanics. If I'm inside a wagon and I pull a spring connected to the wall, will the wagon move? [closed]

Suppose the mass of the wagon is very small. There's a spring connected to the wall inside the wagon. If I pull the spring, does the wagon move?
2
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1answer
72 views

Friction in pulleys

The moment equation of a pulley with a rope applying tension on both sides is as follows: $$I\alpha = f + T_1R - T_2R$$ ( $I$ - moment of inertia; $\alpha$ - angular acceleration; $f$ - friction ...
1
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1answer
36 views

How can a rope's tension be at a maximum as a body is about to move up a slope in the rope's direction? [closed]

Note: I do NOT need this exercise's answer. I have no problem working the math out and noticing the truth of my title. A box of mass 0.5 kg is placed on a plane which is inclined at an angle of 40 ...
0
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1answer
30 views

1D string reflection and transmission phase

Ok, I must be missing something very obvious here. After applying the boundary conditions, we can write: $$ A_R e^{i \delta_R} = (\frac{v_2 - v_1}{v_1 + v_2}) A_I e^{i \delta_I} $$ and $$ A_T e^{...
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2answers
83 views

How do I write the equation of motion for a pulley on a fixed rope? [closed]

I've got complex dynamics problem I'm trying to solve, but the crux of my problem at the moment is describing the path a pulley would take on a rope of fixed length. Assume the rope is fixed at ...
2
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4answers
144 views

Why is the work done by tension in a pulley always zero?

Consider a pulley with a rope around it connecting two masses. According to this post the work done by the rope on the two mass system is 0. The explanation of this post makes sense to me; the blocks ...
0
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2answers
54 views

String and pulley problem doubt [closed]

When we apply a constant force on the massless string as described in the left image, the tension T = F. My doubt : isn't applying constant force similar to a block m2 hanging in the 2nd image. What ...
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2answers
144 views

To find the equation of Motion of a Simple Pendulum using Lagrangian mechanics [closed]

The Equation of the Trajectory of a particle can be obtained by eliminating the variable $t$ as we are doing in the equation of Trajectory of a parabolic Projectile. So, my question is if the equation ...
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0answers
41 views

Foucault's pendulum; ball bearing?

Is is a ball bearing necessary to prevent the cord from twisting in a Foucault pendulum?
1
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1answer
44 views

Work from string wrapped around cylinder [closed]

A cylinder, on a level surface angularly accelerates as a string wrapped around is put under tension. Because this string causes the cylinder to roll without slipping, the tension force cannot to any ...
1
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1answer
75 views

A problem in newtonian physics [closed]

Hello! I have solved problem 89 using analytic way, i.e, the length of the string will always be constant, so repeated substitutions and differentiating will make way(i got answer as "c"). But is ...