tool designed to strike animals or people to aid in guidance or exert control through pain compliance or fear of pain

A whip is a long strand of leather or other fabric with a hard handle. When a person shakes a whip fast, it makes a loud "crack" sound, because it has broken the sound barrier. It is used for directing or hitting animals or people. Some whips are made for corporal punishment.

A whip commonly used to direct an animal
Men with whips in their hands