Now Desmond and Cherie tackle a homework problem. Two wave pulses travel on a string toward each other. The wave pulses can be described as where k = 4 rad/m and w = 7 rad/s. At what instant do 7 5 -5 Y1 = and y = (kx - wt) + 2 (kx + wt - - 6) + 2' the two cancel everywhere? (Assume x is in meters and t is in seconds.) S At what point do the two pulses always cancel? m