Two wave pulses on a string approach one another at the time t = 0, as shown in the figure below, except that pulse 2 is inverted so that it is a downward deflection of the string rather than an upward deflection. Each pulse moves with a speed of 1.0 m/s. Make a careful sketch of the resultant wave at the times t = 1.0 s, 2.0 s, 2.5 s, 3.0 s, and 4.0 s, assuming that the superposition principle holds for these waves, and that the absolute value of the height of each pulse is 3 mm in the figure below.
Picture found at http://www.cramster.com/answers-jan-08/physics/wave-pulses-string-approach-time_167341.aspx?rec=0
Superposition - adding up the amplitudes,
The Attempt at a Solution
I understand that at t = 1.0 and 4.0 seconds, the superposition would be 0, and why t = 3.0 seconds would be the amplitude, 3mm, but I don't know how to find t = 2 and 2.5 seconds. I'm think that if they were simple sine waves, I could just add them, but they are different shapes. Would that affect the amplitude?