In motion pictures, what do you call the lens manipulation where the focus quickly changes from one subject to the next in a motion picture

A film transition is a technique used in the post-production process of film editing and video editing by which scenes or shots are combined. Most commonly this is through a normal cut to the next shot. Most films will also include selective use of other transitions, usually to convey a tone or mood, suggest the passage of time, or separate parts of the story. These other transitions may include dissolves, L cuts, fades (usually to black), match cuts, and wipes.

Explanation:

this could be newton#'s law of cooling. the cooling curve is exponential