The dynamics of Lato Lato ball collisions

Abstract Lato Lato is a toy that consists of two identical solid balls that are secured together with a rope and can be used as a learning tool in physics. In this study, we examined why the Lato Lato toy uses two balls with the same mass rather than balls with different masses. The collision of the two Lato Lato balls can be considered an elastic collision. The two balls move symmetrically at the same velocity and form a semi-circular route with opposing motion directions when we use Lato Lato with the same ball mass ( m 2 = m 1 ). The angular momentum of the two balls is also the same but in opposite directions, so they cancel each other out. Hence, the two balls travel steadily when Lato Lato is performed. This condition leads to a balanced movement of the Lato Lato system and prevents it from collapsing. On the other hand, because of their disparate masses ( m 2 > m 1 ), the two balls of Lato Lato move in an imbalanced manner. A lighter ball travels farther because it moves more quickly than a heavier ball. The angular momentum of the two balls is in opposite directions but not of the same magnitude, so they do not cancel each other out. This results in unstable movement of the two balls when Lato Lato is played. Therefore, the two balls no longer collide centrally, like in Lato Lato, with the same mass, but the collision is glancing. Then, the motion of the two balls facilitates collapse easily. This work can enrich students’ understanding of collisions beyond the collisions of two objects commonly discussed in textbooks.