Name given to a group of weak intermolecular attractions

van der Waals force

Explanation:

The probability of an electron inside an atom  in a specific region at a certain time is termed as the "electron charge density." As there is no way to know exactly where the electron is situated, and since not all electrons exist in the same area at 100 percent of the time when all electrons go to the same area at once, the dipole is created momentarily.

As the nature of molecule is charged i.e. polar, this suggests that almost all electrons are clustered at specific end and the molecule is partially negatively charged at that end. This charged cluster momentarily creates a positive charge on another atom and attracts it to create a weak bond force called van der Waals force.

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.