Unraveling the Physics of Strings: Tension, Velocity & Slope

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SUMMARY

The discussion focuses on the physics of wave motion in strings, particularly addressing the tension in a rotating uniform circular hoop and the behavior of waves at the junction of two strings with different linear densities. Key equations include the wave function y(x,t) = A / (x-vt)^2 + b, where 'b' represents a constant affecting the wave's vertical displacement. The relationship k1v1 = k2v2 is crucial for understanding wave transmission and reflection at the knot between two strings. The assumption that the strings have the same slope at the knot ensures continuity of the transverse tension component, preventing infinite forces.

PREREQUISITES
  • Understanding of wave functions and their mathematical representations.
  • Familiarity with concepts of linear density and tension in strings.
  • Knowledge of centripetal acceleration and its application in rotational motion.
  • Basic principles of wave reflection and transmission at boundaries.
NEXT STEPS
  • Study the derivation of wave speed in taut strings using the formula v = √(T/μ).
  • Explore the implications of the continuity of tension across boundaries in wave mechanics.
  • Investigate the physical significance of the wave number k in wave motion.
  • Learn about the effects of varying tension on wave speed and slope in connected strings.
USEFUL FOR

Physics students, educators, and professionals interested in wave mechanics, particularly those studying string dynamics and wave interactions in different media.

reza1
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Just a couple of Questions:
for the wave function y(x,t) = A / (x-vt)^2+b ------> What is the importance of 'b' and what is its meaning?

A Uniform Circular Hoop of string of mass m and radius r is rotating in the absence of gravity. Its tangential speed is Vo. Its length is deltax=r*delta(pheta)

Find the Tension in the Spring
Linear Density= u
Length = x
Mass = u * delta x
ac=centripetal acceleration
(u*deltax)ac=2Ft + sin1/2(pheta)
(u*r*delta(pheta))Vo^2/r=2Ft1/2(pheta) ---> Assuming small angle for Sin
uVo^2= Ft

Find the speed of a wave traveling on the string
Do i have to find the 2nd derivative of ASin(kx-wt) for the velocity?Another Question
Two strings of Linear Density u1 and u2 are tied together at x=0 and stretched along the x-axis with a tension F. A wave given by y(x,t)=Asink1(x-v1t) travels in the string of linear density u1. When it meets the knot it is both reflected, giving a wave Csink1(x+v1t) and transmitted giving a wave Bsink2(x-V2t)

What is the Physical Interpretation of the assumption that k1v1=k2v2
Just need some help to start this question

What is the Physical interpretation of the assumption that the strings have the same slope at the knot

if the length and frequency of the knot is held constant and the tension varies, both strings will have the same slope ? ---> I am not to sure about this Help on any of these questions will be much appreciated thank yiou
 
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reza1 said:
A Uniform Circular Hoop of string of mass m and radius r is rotating in the absence of gravity. Its tangential speed is Vo. Its length is deltax=r*delta(pheta)

Find the Tension in the Spring

What do you mean by saying that the length of the string is Δx? The derivation you have given is correct, but I'm not sure you have understood the derivation correctly.


Find the speed of a wave traveling on the string
Do i have to find the 2nd derivative of ASin(kx-wt) for the velocity?

Use the same formula for the speed of transverse wave in a taut string.

Two strings of Linear Density u1 and u2 are tied together at x=0 and stretched along the x-axis with a tension F. A wave given by y(x,t)=Asink1(x-v1t) travels in the string of linear density u1. When it meets the knot it is both reflected, giving a wave Csink1(x+v1t) and transmitted giving a wave Bsink2(x-V2t)

What is the Physical Interpretation of the assumption that k1v1=k2v2

What does kv represent in wave motion?

What is the Physical interpretation of the assumption that the strings have the same slope at the knot

The transverse component of the tension, which is -T[itex]\frac{\partial}{\partial x}[/itex] y(x,t) should be continuous across the boundary; otherwise it'll give rise to infinite forces.
 
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