Motion of Plucked String
Why Physics Stack Exchange recommends it
Physics Stack Exchange users link it as a concrete picture of the real wave shape and motion of a plucked string when answering questions about overtones, modes, nodes and damping.
Recommended by 1 people across 1 different months, 2014 to 2024.
What it is
A 1.5 minute clip by Dan Russell (Penn State, acoustics) showing how a plucked string actually moves, filmed and animated so the traveling kinks and the shape of the string over time are visible. It is a short visual demonstration with no lecture.
What people said
Recommends Tricky · 2018-09 · Physics Stack Exchange · on “How are overtones produced by plucking a string?”
An example of the string movement is shown in [this video] (not for a guitar, but its a good example that is relevant).
Cites Chris Degnen · 2014-06 · Physics Stack Exchange · on “Based on note, how fast is a stringed instrument's string oscillating?”
The distance the string moves, i.e. its amplitude, will depend how hard you pluck the string and that will only affect the volume. The pitch is controlled by the string length. The actual wave shape of a plucked string is shown in a video here: Motion of Plucked String [this video]
Cites Vincent Fraticelli · 2022-07 · Physics Stack Exchange · on “How can I calculate the number of nodes on a plucked string?”
Initially, as long as the damping is negligible, there are no nodes on a plucked string (Obviously apart from the two nodes at the ends). The motion is a linear combination of modes which are indeed standing waves with fixed nodes. But their sum is not a standing wave. In the course of time, the modes decay with different typical times and I would tend to think that the lowest mode, with only two nodes at the ends is the one that remains. This is what I think I see in this video: Motion of a plucked string [this video]
Cites Plemath · 2024-01 · Physics Stack Exchange · on “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: $u_{tt}=c^2u_{xx}$ to predict the motion, then d'Alembert's solution is this [LINK] . In reality, when we pluck a guitar string, the motion we observe is definitely not this one. There is vibration but it is qualitatively very different from our solution. It looks like the first harmonic, and there are no sharp corners. Why does this happen? As I explain towards the end, the justification that I find on the internet is wrong. First, here is my partial understanding. At the very beginning of the motion, o
Cites Edward · 2024-09 · Physics Stack Exchange · on “Can taut membranes and strings that are clamped at both ends propagate non-standing waves?”
Is it actually possible to pluck a string and get that result? Here's a video of a real string being plucked: [this video]