Standing Waves figures

1. Jun 25, 2007

BMWPower06

1. The problem statement, all variables and given/known data
The figures below show systems of standing waves set up in strings, fixed at both ends, under tension. All of the strings are under the SAME tension and are otherwise identical, EXCEPT for their lengths. The variables in these situations, in addition to the lengths (L) of the strings, are the amplitudes (A) at the antinodes and the number of nodes in the standing wave.

Which of the following statements are true about the situations depicted in the figures above?

True False The wave speed does not depend on the amplitude of the wave
True False Figure E has a wavelength of 20 cm
True False Figure B has the most nodes
True False All of the standing wave patterns have the same wave speed
True False Figures C and F have the same frequency

3. The attempt at a solution

I looked through my book, and i know that im close, im just not sure which ones are wrong. My answers are in bold, and the computer says its wrong, but not which ones are wrong. Any help?

Thanks

2. Jun 25, 2007

Staff: Mentor

3. Jun 25, 2007

BMWPower06

Well:
1) V= Sqrt T/U so i think thats right
2) Wavelength is from one antinode to another, so i think that is right
3) Figure B has the most frequency so it has the most nodes
5) They both have 3 occurences in the same period so they must be the same

I dunno which is wrong, i tried changing number 4 but that was still wrong.

4. Jun 25, 2007

Staff: Mentor

OK
From one antinode to the next is a half wavelength, but OK.
You can just count the nodes.
What does wave speed depend on?
Why do you think the period is the same?

5. Jun 26, 2007

BMWPower06

4. length and tension/force

5. because they are all in the same window, but im not too sure

6. Jun 26, 2007

Staff: Mentor

Wave speed does not depend on length. Review the formula that you quoted regarding question 1.

The windows are not all the same size. Check the length of each window, which is labeled on the diagram.