What are van der waal forces in detail?

Strength between permanent dipoles:

is the one whose interaction occurs between polar molecules

example:

H-Cl > < H-Cl

The forces of London :

occurs between temporary dipoles or misled apolar molecules.

Read the sentences below in 1962, i tried to enroll as the first black student at the university of mississippi. the governor of mississippi blocked my entrance which best describes the verbs used in the sentences? o they are past tense verbs, which are often used in narrative essays o they are past tense verbs, which are not often used in narrative essays. o they are future tense verbs, which are often used in narrative essays o they are future tense verbs, which are not often used in narrative essays.