(adsbygoogle = window.adsbygoogle || []).push({}); [SOLVED] Mechanical waves

1. The problem statement, all variables and given/known data

Hi all.

Please see the last page in this .ppt (problem 15.66):

http://web.utk.edu/~kamyshko/P232/Problems_13_15.pdf [Broken]

3. The attempt at a solution

Here are my answers - I would be grateful, if you would read them through and comment/help where necessary:

a) Since there are 5000 flashes/min, there's 83,3 flashes/s. I want to find the time it takes for 5 flashes, which is 5/83,3 = 0,06 s. This is the half of the period T (half the unit-circle?), so the period T = 2*0,06 s = 0,12 s.

The frequency is T^(-1), and to find the wavelength, I will use that the string is fixed at both end and since the string isonewavelength long, we can use that the wavelength lambda = L.

b) Since there is only one point not moving, it is the second harmonic (first overtone).

c) To find the speed of the travelling waves, I use that v = lambda*f.

d) To find the speed of point P at position 1, I differentiate y(x,t) w.r.t. t and insert x = L/4 (since P is at the top of the first crest so L/4 horizontal distance from starting point) and t = 0.

To find the speed of point P at position 3, I do the same as above.

e) To find the mass of the string, I use that v = sqrt(F/mju), where mju is mass/unit length.

- Thanks in advance,

sincerely Niles.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Mechanical waves

**Physics Forums | Science Articles, Homework Help, Discussion**