Answer:
Because it unites particle and wave nature.
Explanation:
De Broglie wavelength can be defined as the,

Here, h is planks constant, m is the mass of electron, v is the velocity of electron.
Since the de Broglie wavelength can behave like the photon wavelength with respect to the momentum
It unites particles and waves nature ,so De Broglie wavelengths is probability waves associated with the wave function according to physicists.
I think you need more information like the force of gravity and the force of the three people. Once you combine the two, however, you should get the net force.