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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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0answers
22 views

Acceleration of a pulley [on hold]

In the figure shown, m1=1kg, m2=2kg, m3=0.5kg and m4=4kg. On solving, I observe that the pulley P accelerates downwards. Why does that happen when P has lesser mass hanging from it than Q does? The ...
0
votes
2answers
59 views

Question on using calculus in physics problem [on hold]

I did the following question: A smooth ring of mass $m$ can slide on a fixed horizontal rod. A string tied to the ring passes over a fixed pulley $B$ and carries a block $C$ of mass $M =2m$ as ...
1
vote
1answer
41 views

Work from string wrapped around cylinder [on hold]

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 ...
0
votes
1answer
63 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 ...
0
votes
2answers
29 views

Would equal balance at same height when hung on a balance?

This is based on a question from the gravitation course on Brilliant. As you can see in the diagram below, we have 2 weights hung on a pulley. It is given that: Neither one accelerates when you let ...
0
votes
0answers
26 views

Boundary conditions of spun string

Problem: Consider a string with mass per unit length $\rho$ and length $L$. It is spun about one end, with angular velocity $\omega$ , such that the motion is in a plane (we neglect gravity). Let $x$...
0
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0answers
75 views

Considerations for formulating Lagrangians in general

My question albeit trivial is something I wish to understand better. Given a system either say 3 masses, 2 masses and a pulley (with mass), and 2 masses attached via a string with mass $m$ (and ...
1
vote
1answer
25 views

Equation of constraint - Falling disc unrolling from an attached string

Where does the equation of constraint below come from? I've tried to rationalize it, but the angle will be 0 more than one time as the string unrolls, even though y will keep going down (right?), not ...
0
votes
1answer
27 views

Reflection of transverse wave from free end?

I have been using David Morin' drafts on waves along with French's wave book and Fox Smith's book for my undergrad wave course and one thing I don't understand is the physical intuition behind ...
1
vote
1answer
35 views

What's the relation between the tensions on a rope around a non-ideal pulley? [closed]

I know that on one side of the pulley the tension must be larger to let the torque do its job and rotate the pulley. But how does the relation look like? $$T_1 = k \cdot T_1'$$ What's $k$?
4
votes
2answers
129 views

Tension in a string, at an angle [closed]

This was a question on a mechanics exam. Part i wants me to assume that the tension in both parts of the string is the same. Even though I got the correct answer( 18.9N) by assuming so, I don't ...
0
votes
1answer
33 views

Rings threaded onto strings

This is a follow up question to a question I asked a few weeks ago (Normal contact force with a light string) When a ring is threaded onto a light string, we know it experiences a contact force. Does ...
0
votes
0answers
47 views

How long does it take for a wave pulse on a string to get reflected from rigid boundary?

This question arises from analysis of standing waves.The incident wave has the equation $$y=Asin(kx-\omega t)$$The reflected wave has the equation$$y=Asin(kx+\omega t +\pi)$$When determining the ...
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votes
0answers
28 views

Stationary waves in a string

The narrator says that 'the ends will be taken as nodes' while to generate the wave, the simulation is oscillating the left end. I was taught that a node has zero amplitude; here that is not the case. ...
1
vote
1answer
43 views

How to find the equation of motion for a string threaded through the centre of a table?

A string of total length $l$ is threaded through a hole in the centre of a frictionless horizontal table and then released. How would one go about finding the vertical equation of motion for this ...
2
votes
1answer
80 views

Is the first harmonic the prevalent frequency? [closed]

Why, when we play a string, almost all of the energy we give them is ''used'' in the first harmonic (the fundamental frequency) rather than be distributed between all of them?
9
votes
3answers
971 views

In a ball with random thread/strings, how does the density of threads/strings change with radius?

A large plastic ball full of holes is given. (So the holes are in a plastic shell.) Straight threads connect these holes randomly, by passing through the interior of the ball/shell. For a big ball or ...
0
votes
2answers
48 views

Tension in a string in free fall

A body is attached to another with a string and both are in free fall. How does the tension in the string being zero make sense conceptually?
1
vote
1answer
48 views

Variation of Tension in a rope [closed]

In the 1st picture we consider the tension in the rope to be the same on both the sides. However in the second picture we take it to be different. Why? If we have to consider a general case then why ...
0
votes
1answer
32 views

Ambiguous Constraint equation

This is from the solution manual of some problem of Kleppner's book. I didn't understand how the constraint equation came about to be. First of all, I don't see how that equation is equal to the ...
1
vote
1answer
40 views

Why the capstan equation is exponential? [closed]

Does anybody knows any intuitive explanation about the reason that the capstan equation is exponential and not, as expected, linear?
1
vote
4answers
92 views

How to resolve velocity components?

In the arrangement shown in the figure, the ends P and Q of an inextensible string move downwards with uniform speed $u$, pulleys A and B are fixed. With what speed does the mass M move upwards? My ...
2
votes
0answers
42 views

Prove from first principles that a guitar string will vibrate at a constant frequency

From experience I am aware that a taught string will generally vibrate with a constant frequency. I wanted to prove this by considering the relation of distance from the resting position, and its ...
-1
votes
1answer
49 views

Can this sum be done without integrating?

As by using conservation of mechanical energy, we can just be concerned about the final and initial position and the velocity could be found out. Am I not right? But I am not getting the correct ...
0
votes
1answer
35 views

Do pulleys have no effect on atwood machine?

I was given the following example for an atwood machine: We should calculate the accelaration of the masses. The given solution to this problem was the same as like there is just one pulley: $$a=\...
0
votes
2answers
38 views

Real Pulley and Newton's Third Law

In a real pulley with two masses hanging from either side, the pulley rotates due to a non-zero torque, which I understand is caused by friction on the rope. I understand that if each mass was ...
0
votes
1answer
46 views

A spinning pendulum [closed]

I just thought of a scenario : We rotate a sphere that is hanging from a string about vertical axis and then allow it to oscillate like a pendulum . Will its time period differ from a sphere ...
6
votes
3answers
150 views

Vibrating string as a dynamic system

It's known first order dynamical systems had one energy storage (example C, in RC circuits) these systems act as a filter but don't resonate, on the other hand a second order system had two energy-...
11
votes
4answers
3k views

If all harmonics are generated by plucking, how does a guitar string produce a pure frequency sound?

A guitar is a plucked instrument and it is played by plucking a string at an off-centre point fixed at two ends. In general, Fourier analysis tells that all harmonics (the resonant frequencies of the ...
1
vote
3answers
43 views

Force required to lift a block [duplicate]

Let us consider block of mass $m$ hanging by rope with force $T$. When no other horizontal and vertical forces are acting on a block, the block is at equilibrium if $$T=mg.$$ And if the rope is pulled ...
0
votes
1answer
37 views

How to draw diagrams of Path, velocity and time for a complex problem?

What does an approach or a solution strategy look like for the following problem: Two point-shaped bodies with the masses m_1=100g and m_2=200g are connected to a string of 30 cm length and lie on a ...
1
vote
1answer
21 views

To isolate a particular mode of vibration in a standing wave on a string

Suppose a string bound between two rigid end-points is vibrating and it is a combination of a number of normal modes of vibration, is it possible to isolate a particular mode of vibration in wave by a ...
2
votes
1answer
64 views

Stupid pulley question [closed]

I started self-studying physics and it's been 15 years, since I took basic mechanics in college. It seems to me that I'm unable to figure out how to rigorously derive from Newton's laws how a basic ...
0
votes
0answers
32 views

Confusion about valid set of virtual displacement

The answer of the problem below makes me confused about my thinking about virtual displacement... Consider the system in the figure below, similar to mechanisms used for aerial filming of sporting ...
0
votes
0answers
33 views

When does a steel cable snap?

We have a woven cable made up out a large number of thin single strings of steel. Let's make the assumption the strings don't get deformed. Now the strings are not all equally thick, so let's make the ...
0
votes
1answer
76 views

Pulling a string with both ends fixed [duplicate]

Consider a string with both ends fixed. If somewhere in middle of it be pulled and released, how would it oscillate and what is it's equation? My solution assuming the result is a standing wave: The ...
0
votes
0answers
22 views

Tension: Forces on a string [duplicate]

Suppose a mass hanging from a string which is fixed from a beam on top. The mass will pull string with same force as its weight. String will also try to pull beam with same force and according to ...
-1
votes
2answers
72 views

Question regarding a wave problem [closed]

An example problem from my openstax physics textbook: A student takes a 30.00-m-long string and attaches one end to the wall in the physics lab. The student then holds the free end of the rope, ...
0
votes
1answer
44 views

Stress tensor of a rope in equilibrium [closed]

First of all, let me say that I'm not a student of physics but of mathematics, so please be comprehensive. I'm currently studying continuum mechanics. As an example of applications of Cauchy stress ...
-1
votes
2answers
80 views

Question about pulley

I am wondering if the tension in the ropes in this situation is the same. Doesn't it matter if the other rope is pulled at an angle? Does this change the tension in the rope? For example if at one ...
1
vote
1answer
54 views

The length of a string attached to a wall?

I feel really dumb for asking this question. I apologize in advance. When the example of a string attached to a wall is given to explain waves and the ressonance frequencies, the length of the string ...
1
vote
1answer
53 views

Calculate the length of the string if it is vibrating at the 4th harmonic [closed]

The statement is as follows: The function that describes a standing wave on a fixed string at both ends is given by $y(x, t) = 2A \sin (kx) \cos (\omega t)$, where $A = 1.5\ \mathrm{cm}$, $k = 0.3\ ...
0
votes
1answer
42 views

Derivation of acceleration and tension of pulley system [closed]

On this website I am considering the question that goes along with figure 30. I am going to assume downwards is negative and rightwards is positive (not to confuse upwards as the website says). The ...
0
votes
1answer
56 views

Does the rope stretch when the pulley of Atwood's machine is accelerated?

Let's say I've an Atwood's machine in which I have two point masses which are different. Now, when I accelerate the pulley, the two masses accelerate at a different rate which can be shown by ...
0
votes
4answers
69 views

Tension at extreme of a rotating rope of mass $m$

A uniform rope of mass per unit length $\lambda$, length $\ell$ is attached to shaft that is rotating at constant angular velocity $\omega$. Find the tension in the rope as a function of distance ...
0
votes
1answer
47 views

Gravitational force on a rope

If we have a rope fixed to the ceiling. How much gravitational force will the rope experience? Let's suppose the mass is $m$. Well the obvious answer is $mg$. But doesn't the part that is ...
0
votes
0answers
33 views

Is the Euler-Eytelwein equation also applicable for sliding friction?

Is the Euler-Eytelwein equation also applicable for sliding friction? Does this hold true if you just replace the coefficient of static friction with the one of sliding friction? I'm working on a ...
1
vote
2answers
141 views

How does the thickness of a string affect the frequency?

I've notice that thicker strings have lower frequencies, but is there a specific relationship between theses two?
3
votes
1answer
62 views

Why a rope grabbed by a single end seems to follow the hand that grabs it?

Context I am thinking about the physics of the movement of a rope in the context of a person running and grabbing a rope in one hand (the other end is "free", there is nothing attached). When the ...
1
vote
3answers
397 views

Still Confused about Linear Momentum in a Circle

A point mass with mass $m$, distance $r$ from circle and constant tangential velocity and constant angular velocity is swung around a circle. ($p$ is linear momentum) Angular momentum is radius x ...