# 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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### Pulley acceleration [closed]

I got a3 and a2=0, and a1=a, and mg-2T=ma. How to proceed further?
37 views

### Constraint motion question [closed]

I found difficulty in solving this question. I tried setting up the equations of motion and free body diagram like such [insert math or equations and key concepts], and computed the result [enter ...
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### Double Atwood's Machine Problem [closed]

I'm trying to find the Acceleration of each mass. so far I managed to find a1 (hopefully) can someone validate my work so far? (except the neg sign I missed on the final answer)
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### Classical mechanics pulleys, Something is wrong with my workings out, non-convergent sum? [closed]

Find the acceleration of any mass for this type of system. At the lowest pulley there are two masses connected, $m_n$ and $m_{n'}$. I having a hard time tackling the finite problem but the solution as ...
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1 vote
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### Why is resolving vectors in some ways WRONG?

The following question is from "Concepts of Physics" by H. C. Verma. A man has fallen into a ditch of width $d$ and two of his friends are slowly pulling him out using a light rope and two ...
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### How does each team pull the opposite team with equal force in tug of war by Newton's third law? [duplicate]

How does each team pull the opposite team with equal force in tug of war by Newton's third law? Is it even related to the third law? If a man A on right pulls the rope with 50N force, is it necessary ...
488 views

### Why does the block move if the net force is zero?

In free space an end of a rope is attached to the left side of a block, the other end is freely floating. An astronaut (on the other side of the block where the rope isn't) pulled the block by 5N ...
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### Spring hanging on a spinning Disk

I have already asked a question on the Math stack-exchange. You can find it under the following link: https://math.stackexchange.com/q/4876146/ I felt like the question is better suited for this stack-...
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### A body on which the net force is zero but is still accelerating with respect to the question below [duplicate]

First of all thank you so much for reading, I was trying to solve the question below from "Concepts of Physics Vol1" by HC Verma. What I was most interested in was the second part, "...
261 views

### Infinite force paradox in pulling a car out of mud

Consider a car stuck in mud. A way to pull the car out would be tying a rope with a tree and pulling on the rope perpendicularly, at the midpoint: This works well as it magnifies the force depending ...
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### Is sound louder in a solid compared to air?

Consider this experiment, where it is shown that the sound of the metronome is louder when you hold the acoustic sensor directly towards the table. Many explanations in the internet argue that it is ...
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### Question about waves in a fixed string

consider a string that is fixed at both ends. This string is connected to a metal stick. When I hit the metal stick, sound waves (longitudinal and transversal ?) will propagate trough the metal and ...
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### Reasoning behind failure of string constraint in acceleration but not velocity

As I understand it, the string constraint used in mechanics with an ideal string is derived from the fact that the length of string always stays the same (provided it is under tension and not slack). ...
1 vote
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### Resonating string with increasing amplitude

The situation goes like this: We have a tuning fork at one end of a string (whose other end is fixed to a wall and length $L$). The fork is vibrating with small amplitude so we approximate this end of ...
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### Confusion in conservation of momentum [closed]

Two masses $m_1$ and $m_2$ are attached to the two ends of a rope that is sent through a pulley. Then a mass $M$ is dropped onto the mass $m_1$ from a $h$ height. So when the law of conservation of ...
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### What are the acting forces in the tug of war problem? [closed]

My intuition says that person 1 exerts a force $F_{1}$, but it's not exerted on person 2, rather, it is exerted on the rope in between. So far so good. From Newtown's third law, the rope exerts a ...
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### How does a guitar string produce sound?

I'm curious about the mechanism of a guitar producing sound. Of course, I know once a string is plucked it vibrates in a superposition of several harmonics, but what I don't know is what happens next. ...
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### Difference in kinetic energy when one block has velocity in a system of two blocks connected with inextensible string and other block at rest

Why is there a difference in kinetic energy in case of when a single block in a two rigid block system of masses connected with an inextensible string has a velocity while the other block is at rest ...
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### Torque at only two points of contact between a rope and a disk (rigid body dynamic)

In physics, particularly when dealing with rigid bodies, there's a common practice of calculating torque at only two points of contact between a rope and a rotating disk, typically at the extremes ...
60 views

### Proof regarding $\sum\vec T_i\cdot \vec a_i=0$ this relation for a pulley mass system [closed]

How to prove that for a system containing more than one pulley and more than two masses this relation will hold. $$\sum\vec T_i\cdot \vec a_i=0$$ where $T_i$ and is the tension acting on the $i^{th}$...
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### I cannot understand the way these questions were solved [closed]

I was going through the mcqs of my physics book and i stumbled upon this pair of questions. Source of images: vaia.com 1.Figure gives a snapshot of a wave traveling in the direction of positive xalong ...
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### Which accelerates more? A pulley of constant diameter or a pulley of decreasing diameter? [closed]

Given two pulleys. One is a straight drum for the rope to wrap itself around while maintaining a constant diameter as the rope unwinds. The other is a a drum with a spiral that the rope winds itself ...
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### String pulling sides of a triangle inwards: Force acting on each side?

Referring to the image above: The black lines are ONE continuous string whose ends are where the red thing is. The red thing can tension the string and can measure the force used to tension the ...
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### Tension in a falling rope attached to a support

I came across this question and thought it was fairly simple. Here is what I did: The rope is slack at the lowest point. At t = 1, this point is at 2.5m below the support. we can say the tension is ...
1 vote
59 views

### How do I know when in rotational dynamics whether or not mechanical energy, translational momentum, and angular momentum are conserved?

In trying to solve this particular problem: I have become confused about the conservation of energy and momentum. Specifically for Case A would angular momentum be conserved because there is net ...
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### Rope over an un-ideal pulley in an Atwood's machine

Please consider a pulley with a taut rope over it and two objects (with different masses m1 and m2) hanging on each side. The pulley is not negligible - it has a mass Mp. In the solution to a problem ...
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### Frequency, if any, of a string with two different thicknesses [closed]

Very brief question. Assume a string that is made half out of a thin rope and half out of a thick rope (the thick rope is heavier of course). A transverse mechanical pulse is applied at one end (...
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### Why is energy conservation not valid here? [closed]

I was solving this question and I faced a problem : See the problem is I know the conventional way of impulse momentum and energy conservation to solve this question but , I do not know why applying ...
1 vote
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### Interference of wave on string [closed]

Can somebody explain how the sinusoidal wave will cross the junction, meaning what will be the intensity and amplitude during and after the crossing? Assuming constructive interference at the second ...
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### Average resultant length $L$ of an active string initially of length $L_\mathrm{0}$ after a single point mutation

I stumbled upon this research article, where they define a digital organism as an abstract minimal model of an evolving predator-prey system as follows: An organism is defined via its genome of fixed ...
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### Topic: Atwood's Machine. Can someone please explain to me how the coordinates are assigned in this question? (Competitive physics by Ricardo) [closed]

Where did 0 come in the first string? Also, I just wanted to know if my understanding is correct when it comes to identifying the strings... I highlighted the ones that I believe are the sets of ...
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### How tension acts in the rope in the pulley system?

I am a high school student and I am a little confused about how the pulley system works here Here in this example below, we always only shown tension on points A and B as acting upwards and then we ...
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### Intuition regarding how tension works

Here is a mock scenario I have to illustrate my confusion,the regular basic assumptions here apply ie smooth floor so there is no friction and air resistance, and a inextensible string . There is a ...
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### How was the reference system taken here?

in this Atwood machine digram y1 is the amount that m1 gets displaced and y2 is the amount that m2 gets displaced the lecturer then wrote $y1=-y2$ , I am trying to understand what did he do to get ...
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### Why is $R$ not the Radius of Curvature, here? Or is it?

Consider this question, Two masses A and B are connected by a massless string. A rest in equilibrium on a rough horizontal table and limiting friction is acting on it. B hang vertically at a distance ...
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### Vibrating string and damping

Suppose we have a string (in tension) with its ends fixed. Think of a guitar string. Suppose we start with a plucked initial position and we let the string free. If we use the wave equation: \$u_{tt}=c^...
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### Two cars are connected to a string, parked on a slope. What happens? [duplicate]

I would like to ask something, which I would expect to have the same answer as the one to my previous question. But I'd like to be sure and further my understanding: A mass is hanging by a thread from ...
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### A mass is hanging by a thread from another mass, which starts to fall. What happens and why?

Please consider the following situation (ignoring air friction, and assuming all strings have no mass): Ball A with mass m1 is hanging from the ceiling by the blue string. Ball B with mass m2 is ...
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### Tangential acceleration and acceleration of blocks [closed]

I encountered this problem while working on this exercise. The question is to find an expression for the acceleration of the two blocks. I started with writing newtons second law for the two blocks ...
1 vote