• Support PF! Buy your school textbooks, materials and every day products Here!

Fundamental frequency of a stretched string

  • Thread starter lykan_004
  • Start date
  • #1
4
0

Homework Statement



The fundamental frequency of a stretched string is 200Hz. when the length of the string is doubled and Tension of the string made 100times the initial Tension, what is the new fundamental frequency of the string.

(1) 50 Hz (2) 100 Hz (3) 200Hz (4) 400 Hz (5) 800 Hz

Homework Equations



F = 1/2L x sqrt(T/ m)

The Attempt at a Solution



The answer I get is 1000Hz.
 
Last edited:

Answers and Replies

  • #2
993
13
correct attempt
 
  • #3
4
0
does that mean the question is wrong? coz there are similar questions, and i dont get the correct answer for any of them.
 
  • #4
gneill
Mentor
20,792
2,770

Homework Equations



F = 1/2L x sqrt(T/ m)
I think you'll want to verify this formula. It seems to be missing a factor of L inside the square root. You can verify by checking that the units don't work out to Hz in its present form.
 
  • #5
4
0
I think you'll want to verify this formula. It seems to be missing a factor of L inside the square root. You can verify by checking that the units don't work out to Hz in its present form.
m - linear density here not mass..that makes the equation dimensionally correct.
 
  • #6
gneill
Mentor
20,792
2,770
m - linear density here not mass..that makes the equation dimensionally correct.
Ah. Perhaps then [itex]\rho[/itex] would have been a better choice of variable name :smile:

So it would appear that your answer is correct; The frequency should change by a factor of [itex]\sqrt{100}/2 = 5 [/itex]. It sometimes happens that the provided answers are not correct.
 
  • #7
4
0
u r rite .. i wonder the same thing... :) but i hav no idea why they use m.
 

Related Threads on Fundamental frequency of a stretched string

  • Last Post
Replies
1
Views
18K
  • Last Post
Replies
5
Views
19K
Replies
1
Views
29K
Replies
1
Views
7K
Replies
31
Views
2K
Replies
5
Views
12K
  • Last Post
Replies
9
Views
3K
Replies
1
Views
1K
Replies
1
Views
1K
Replies
12
Views
13K
Top