Transverse wave on a string

  • #1
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Homework Statement



Two long strings P and Q ,each having linear mass density 1.2 x 10^-2
are stretched by a different tension 4.8 N and 7.5 N respectively and are kept parallel to each other with their left ends at x=0.Wave pulses are produced on the strings at t=0 on string P and at t=20ms at string Q.When and where will the pulses on Q overtake at on P.

Homework Equations




The Attempt at a Solution



Using the wave equation for the string ,I found the velocity at x=0 for P and Q to be 20m/s and 25m/s respectively.But I have one doubt about this question.Shouldn't speed of a wave in a string change with respective positions due to change in tension throughout the string......So does this not contradict the question
 
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Answers and Replies

  • #2
Orodruin
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What change in tension?
 
  • #3
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Change in tension in a rope having masses incrases linearly throughout the rope
 
  • #4
Orodruin
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You are thinking of a freely hanging rope. There is nothing in the problem formulation indicating that this is the case.

Also, you should always state units when giving values.
 
  • #5
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What is the difference between freely hanging rope and this case?

I will keep in mind to mention the units next time .
 
  • #6
Orodruin
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A hanging rope has a gravitational force acting on it in its longitudinal direction. For force equilibrium, this means tension has to vary accordingly.
 
  • #7
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And what does this case look like...are we holding the rope?
 
  • #8
Orodruin
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The strings are kept taut by pulling them at each end.
 
  • #9
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Okay.I got this then

Thanx
 

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