When two disturbances in opposite directions meet along the medium, the resulting disturbance is determined by the principle of superposition. According to this principle, the resultant displacement at any point is the algebraic sum of the displacements due to individual disturbances.

In other words, when two waves meet, the resulting wave will have an amplitude that is the sum of the amplitudes of the individual waves. The frequency and wavelength of the resulting wave will be the same as the original waves.

If the two disturbances have the same amplitude and are in phase, they will interfere constructively, resulting in a disturbance with twice the amplitude of the individual disturbances.

If the two disturbances have the same amplitude but are out of phase by 180 degrees, they will interfere destructively, resulting in a disturbance with zero amplitude.

If the two disturbances have different amplitudes and are out of phase, the resulting disturbance will have an amplitude that is somewhere between the amplitudes of the individual disturbances.

The exact nature of the resulting disturbance will depend on the specific details of the two disturbances, such as their amplitudes, frequencies, and wavelengths.