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

Find wavelength for a standing wave

  • Thread starter jwxie
  • Start date
  • #1
280
0

Homework Statement



Two sinusoidal waves with identical wavelengths and amplitudes travel in opposite directions along a string with a speed of 10 cm/s. If the time interval between instants when the string is flat is 0.50 s, what is the wavelength of the waves?

Homework Equations



v = w/k = lamda * frequency


The Attempt at a Solution


The solution gives T/2 = 0.50 and T = 1 s
Why do we have to multiple by two???? In fact, if I didn't take twice the given time, i would have this
frequency = 1/T = 0.5 still which doesn't make sense.....

How does "time interval between instants" implies twices? I know between is used when comparing two things. But I just thought that 0.5 was the time the string stayed flat.
Thank you very much.
 

Answers and Replies

  • #2
ehild
Homework Helper
15,477
1,854
A sine function takes the zero value twice during a period T. (sin(0)=sin(pi)=0) If the time interval between successive zero values is 0.50 s the whole time period T is twice as long: 1.00 s.

ehild
 

Related Threads on Find wavelength for a standing wave

  • Last Post
Replies
2
Views
1K
Replies
0
Views
17K
Replies
4
Views
39K
Replies
3
Views
771
Replies
2
Views
3K
Replies
6
Views
2K
  • Last Post
Replies
8
Views
3K
Replies
7
Views
24K
  • Last Post
Replies
1
Views
2K
Replies
1
Views
1K
Top