Two pulses in a stretched string whose centers are initially $8 cm$ apart are moving towards each other as shown in the figure. The speed of each pulse is $2 cm/s$. After $2 s$, the total energy of the pulses will be

After $2 s$, the each wave travels a distance = $2\times 2=4 m$.
The wave shape is shown in figure.

Aftertwo seconds the string will be straight, all particles of the two pulses are passing through their equilibrium position 

with maximum kinetic energy .
 

Thus energy is purely kinetic.