What are the ranks of cops in the U.S. and the corresponding work typically done by each rank?

Here is the LAPD(with job descriptions for each):

“Sworn Police Officer Class Titles and Job Descriptions

The following list represents the various class titles of sworn LAPD police officers. For a description of the job duties for each class title, click below.

Police Officer

Police Detective

Police Sergeant

Police Lieutenant

Police Captain

Police Commander

Police Deputy Chief

Chief of Police”

There are too many separate police forces to give you one comprehensive list. @marinelife‘s list is a good representative sample however.

It depends entirely on the jurisdiction. Some smaller communities don’t even have police departments; they rely on a local sheriff’s office.