Add the displacements
y = yA + yB
Add the signed displacement of both pulses at each position. The solid line shows the actual rope shape. Dashed lines show the two contributions.
When two pulses meet
Watch their displacements add as they pass through each other.
Pulse A Travels right →
Pulse B Travels left ←
LIVE SIMULATION
t = 0.00 s
Pulse A · dashed
Pulse B · dashed
Resultant · solid
Horizontal square = 1 distance unit · Vertical square = 1 displacement unit · Each pulse travels at 2 distance units/s
Follow the pulses: t = 0 to 4 s
Select a snapshot to inspect that moment above.
What happens at t = 2 s?
Try two positive pulses. Then make one negative. Finally, give them different durations.
Does a flat rope at one instant mean the pulses have disappeared permanently?