I am not a teacher, but here's what I think. The active verb, "forced" (past tense), causes the passive verb, "go" to be an infinitive. Therefore, you must use the infinitive form, "to go".Robin forced the sheriff go.
The correct version would be, "Robin forced the sheriff to go."
Some other verbs in infinitive form:
- to stand
- to talk
- to eat
- to sing