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.
1,343 questions
4
votes
3
answers
349
views
Longitudinal waves in a tin can telephone
What kind of wave travels true the string of a tin can telephone? Most places say that its a longitudinal wave, if that's the case then why when the string is tensioned the message gets louder?
- 49
4
votes
1
answer
188
views
Two spools linked via a pulley: only one rotates. How to conserve energy?
I know how to get the correct answer for the following problem using dynamics, but when I approach it using the energy formulation I get the wrong answer.
Two massive, identical spools are attached to ...
- 43
2
votes
1
answer
203
views
Vibrating string at many frequencies at once [closed]
I understand standing waves . When it vibrates faster it pushes air faster higher frequency . What about a plucked string? Does different segments have their own standing wave as the string as a whole ...
- 31
0
votes
2
answers
117
views
Advice for problem solving with Newton's laws of motion [closed]
I'm having trouble solving problems like this. Which actual fundamental concepts should I review again, and which types of problems should I practice again?
5
votes
2
answers
636
views
Is not pulling a massless spring after hanging it equivalent to pulling it from both sides?
Let us hang a massless spring and pulled it downwards with force $F$. (You may neglect gravitational force or include it within $F$.) Let due to this the spring extended by $x$. Now let me pull the ...
- 432
8
votes
5
answers
645
views
Fixed vs free ends in 1D standing waves
In introductory physics courses one often discusses standing waves on a string with two fixed ends. A standard experimental demonstration of this is given here.
My problem is that in such a ...
- 2,018
1
vote
2
answers
51
views
Can a Massless Pulley with no friction be treated as a massless circular object with no friction?
A pulley usually involves a rotating axle to change the direction of tension. However I read in my Textbook that for an ideal pulley, this need not be the case, and you do not need to consider any ...
- 15
2
votes
2
answers
98
views
Will a frictionless rope in space retain its shape if all segments move tangentially with equal velocity?
Suppose we have a uniform, massive, flexible, frictionless and non-stretchable rope in space, initially shaped arbitrarily. Each infinitesimal segment of the rope is given the same velocity in the ...
- 123
0
votes
2
answers
91
views
Confusion in finding stress in accelerated body
On the left side, my teacher shows the method for finding stress on a small element dx of a rod. He treats the tension as the restoring force.
However, my question concerns the diagram on the right ...
2
votes
1
answer
133
views
Position-independent horizontal forces in catenary chain
In deriving the differential equation for a catenary chain, one key assumption is that the magnitude of the horizontal forces is independent of time. If we look at the diagram below
(reproduced from ...
- 133
-3
votes
2
answers
171
views
Pulley paradox, please help [closed]
The same string connects massless pulleys 1, 2, 3 (pulleys 2 and 3 are fixed). What is the force F'? If tension is uniform in the string then it seems like it can not be 2F, but then pulley 1 would ...
8
votes
2
answers
2k
views
What keeps cotton thread together and why does old cotton thread becomes easily torn apart?
One of my old t-shirts recently got a tear. When I pull near the tear, it easily tears more and more apart. When I looked through 20x magnification, I don't see difference of thread in place where it ...
- 865
0
votes
3
answers
157
views
Why does a pulley with friction cause tension in a string to be unequal?
Hello kind people,
Suppose a light, inextensible and taut string that passes over a pulley while holding two objects of masses m1 and m2 is released from rest. The object of mass m2 moves downwards ...
-1
votes
1
answer
114
views
How do I make sense of the wavelength for the second harmonic?
This is probably a very elementary question, but for the second harmonic, we have $L=n\lambda/2=\lambda$.
But how does this make sense?
$\lambda$ is the distance between the two ends of the string. ...
- 1,119
7
votes
5
answers
1k
views
How do guitar pickups measure change in magnetic field?
Let's consider a simplified model of a guitar pickup, which is basically a bar magnet with a coil wrapped around it like so:
The principle of operation is that a ferromagnetic/iron string moving in ...
- 73