The discussion revolves around a physics problem involving two equal spheres suspended by strings and a third sphere that strikes them. The key points include the conservation of momentum and energy during the elastic collision, with specific focus on the horizontal and vertical components of motion. Participants emphasize that vertical momentum is not conserved due to the impulsive tension in the strings, while horizontal momentum is conserved. The conversation also highlights the need to decompose the momentum into respective directions to set up equations that relate the impulses and velocities post-collision. Ultimately, the participants work towards finding the impulse of tension in the strings and the velocities of the spheres after the impact.