i conserved energy.

my theory is that if the spheres should touch at the end.. then that means that after touching they will move apart.

for them to move apart, the final energy of the system must be positive. negative final energy means a bounded system, and we dont want that.. so i thought this was worth a try.

i knew ofcourse that my reason does not explain how they touch each other.. but i was just hoping that the question wnated us to assume what i assumed..

if u know the soln pls tell it.