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Stucked in a Qn on wave.

  • Thread starter Wen
  • Start date
  • #1
Wen
44
0
A rope of total mass M and length L is suspended vertically.Show that a transverse wave pulse travel in the length of the rope in a time t=2(L/g)^0.5

If i take the distance of any point on the rope ,A, from the lower end to be X.
linear density is M/L
Tension due to the segment of rope below A is MgX/L
velocity =(T/linear mass density)^0.5
=(L^2/Xg)^0.5
if X=L
V= (L/g)^0.5

which is not what is needed to be shown. So where am i wrong?
 

Answers and Replies

  • #2
mukundpa
Homework Helper
524
3
Wen said:

velocity =(T/linear mass density)^0.5
=(L^2/Xg)^0.5


Check your calculations !!! and write [tex] v = dx / dt [/tex]
 
  • #3
quasar987
Science Advisor
Homework Helper
Gold Member
4,775
8
The speed of the wave is not constant. It diminishes as the wave gets closer to the lower end. So to find the time, you have to integrate dx/v.

(And yes, check your calculations :tongue2:)
 

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