# 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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### How can I accelerate the linear speed of a spinning rock on a string when the rope can exert no net torque on the rock?

If I take a rock attached to a mass-less rope and start spinning it over my head (or on a friction-less surface, I don't think it matters) I can accelerate the linear speed of the rock (I can spin it ...
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### Solving this problem using the Work-Energy Theorem [closed]

A block is tied to a string wound on a cylinder of mass $m$ and radius $r$, (Through a pulley) which can rotate about its axis on a massless mount placed on a smooth surface. The system is released ...
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### Why we want the string to be massless in the ideal model of simple pendulum?

I couldn't think about a reason why the string must be massless. Wouldn't the assumption that the air resistance is negligible, the angle $\theta$ is small and the string is non-stretchable suffice ...
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### Pulley system with constraints

Now I need to find out the acceleration of pulley A. I know that (acceleration of a) = 2(acceleration of c) and the accelerations of A and C are in opposite directions using constraints. The solution ...
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### Final position of weight hanging from two opposed pulleys on ropes

Let's say I have the situation pictured below. The red and green ropes are tied to immobile supports. The ends of the red and green ropes are attached to frictionless rings. The blue rope is tethered ...
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### Boundary condition on a finite vibrating string with forced vibration

Context Considering a finite string of length $L$. We suppose gravitation is negligible. The string is only moving transversaly, in $y$ direction, with small amplitude. The tension of a string is $T$. ...
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### Motion involving Constraint relations

We have the setup as shown in the picture. Two blocks A and B are connected by a string that always remains taut. Block A is on a frictionless surface. Block B is being pulled downwards with a ...
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### Tension in the given situation

Here two equal masses $m$ are hanging. We have to find tension in wire AB and wire CD. Assuming the tension in wire be $T$, I can't figure out why the tension in CD is 2 times to that of in wire AB. ...
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### What is the motion path of each point on the rope? How is the tension calculated? [closed]

The blue line is the rope. Suppose point A of the rope moves upward and point B does not move, what is the motion path of each point on the rope? How is the tension calculated?
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### Friction and Newton's Laws of motion

I came across the following problem. Ok, I thought that assuming there is no friction between blocks B and C, when the blocks B and A will move, the block C will go to the right due to the force by ...
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### How much does string material elasticity affect tension at pitch for a stringed instrument?

In introductory physics classes, we see the simple string oscillator equation, which can be used to estimate the string tension at pitch for a stringed instrument. However, the equation assumes an ...
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### Linear wave superposition along a rope/string

This question basically roots to fundamentals of waves which is quite difficult for me to visualize. Hope that I can clear out this confusion based on answers to this question Would be grateful if ...
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### How is tension act microscopically in a string?

Think of a massless string that goes through two pulleys attached to a roof, also massless, and look at this scenario as if you were seeing the string in its atomic constitution, looking at the parts ...
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### Will splitting a tensed string by the ends and in the middle make the two long parts not go flying around?

If you chop a guitar string with 3 swords at the exact same time: ------------ to -|-----|-----|- Would the 2 big parts not move ...
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### Balance equation for a string-spring system: meaning of 2nd Newton's law for massless objects $m=0$ [closed]

The usual homogeneous one dimensional wave equation for transverse (vertical) vibrations is given by $$u_{tt}-a^2u_{xx}=0,\qquad a=\sqrt{T/\rho}$$ where $u=u(x,t)$ is the vertical displacement, $T$ is ...
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### Potential Energy for Non-conservative Forces

I was studying for the GRE and came across the problem below. A small puck of mass $M$ is attached to a massless string that drops through a hole in a platform, as shown in the diagram above. The ...
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### Necessary speed for being at rest

In the figure above mass $m_1$(1.5kg) is rotating with uniform speed in a circular path of radius $r$ and mass $m_2$(2kg) is tied to $m_1$ with a thread. The coefficient of friction on the table is ...
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### Will two bodies initially connected to and revolving around each other, start spinning when disconnected?

Two extended bodies are connected with a string and revolve around each other (that is, around the center of mass of this system). No gravity, no external forces. The string is cut, and they start to ...
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1 vote
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### Application of conservation of momentum to this system has absurd implications

The system, everything shown in the picture (table, pulley, spring, string, blocks, wall), was initially at rest, with spring unstretched. Friction is absent everywhere, and spring, string, and pulley ...
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### How to apply force due to change in momentum? [closed]

The given problem states that A rope is fastened at both ends to a ceiling, one end is allowed to fall freely. Find the maximum force that the fastening at the other end must be capable of handling. ...
1 vote
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### Why is tension force in a string non-conservative?

I have this doubt for quite a while now. Suppose we have a massless inextensible string with tension as 'T', now, I would like to know that is this tension a non-conservative force? If yes, then what ... 