Answer:
Part a)

Part b)
Here final kinetic energy is more than the initial kinetic energy
This increase in kinetic energy is due to spring connected between them as the spring energy is converted into kinetic energy of two blocks
Step-by-step explanation:
Part a)
As we know that there is no external force on the system of two gliders
So here we can use momentum conservation for two gliders
So we will have




Part b)
now we will have
initial kinetic energy of both gliders is given as


Final kinetic energy of two gliders


so here final kinetic energy is more than the initial kinetic energy
This increase in kinetic energy is due to spring connected between them as the spring energy is converted into kinetic energy of two blocks