Understanding Nodes and Frequencies in a Uniform String Under Tension

AI Thread Summary
The discussion focuses on calculating the frequency of a uniform string under tension, specifically addressing the fundamental mode and the impact of creating a node by touching the string. The fundamental frequency is determined using the formula ω = √(T/μ) * nπ/L, resulting in approximately 62.83 radians/second for n=1. When a node is created at 0.5 m from one end, the string's effective length changes, leading to confusion about whether to adjust the length or the harmonic number. The concept of nodes is clarified, emphasizing that nodes are points of no motion, and the standing wave pattern must be drawn to visualize the situation. Understanding these principles is crucial for solving similar problems in wave mechanics.
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Homework Statement



A uniform string of length 2.5 m and mass 0.01 kg is placed under a tension of 10 N.

1. What is the frequency of the fundamental mode?

2. If the string is plucked and is then touched at a point 0.5 m from one end, creating a node, what frequencies persist?

Homework Equations



\omega = \sqrt{T/\mu}* n\pi/L where \mu = M/L

The Attempt at a Solution



I got the first part, I just plugged all the given information into the equation and used n=1 since it asked for the fundamental mode. I got 62.8319 radians/second.

I'm a bit lost as to what the concept of a node is. Do I just use the same equation again, but use L = 2.5 - .5 = 2 m? Or do I use n=5 since the string is now divided into fifths?
 
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Supposed the string is fixed at both ends, its length is equal to a half-wave in the fundamental mode. There is no motion at a node. Draw the standing wave when there is a node at 0.5 m from one end. Where are the other nodes?

ehild
 
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