Here's how they differ in meaning:
* Passed: This refers to the action of going by or moving from one point to another. It can also mean to have successfully completed something.
* Past: This refers to a time that has already happened, or a time before the present.
Example:
* "The car passed me on the highway." (action of going by)
* "He passed his driving test." (successfully completed)
* "In the past, I used to live in New York." (time before present)