15. Two traveling Waves!


We have chosen the x-axis to have a length of exact number of half-wavelengths (four (l/2) in this case. By pressing the F9 key, you can see how at both ends (and also for values of x = n l/2, n = 0, 1, 2,..), we always have the same value with opposite signs for the two waves; therefore the second wave can be thought of as the ‘hard’ reflected wave at the right end. This is the situation we have for a transverse vibration set up in a stretched string with fixed end.

Note at x = (n+1/2) l/2 they have exactly the same y value with the same sign.