physical pendulum vs pendulum

physical pendulum and pendulum both are nouns.

Word	Noun	Adjective	Verb	Adverb
physical pendulum	Yes	No	No	No
pendulum	Yes	No	No	No

As nouns, pendulum is a hypernym of physical pendulum; that is, pendulum is a word with a broader meaning than physical pendulum:

physical pendulum: pendulum consisting of an actual object allowed to rotate freely around a horizontal axis
pendulum: an apparatus consisting of an object mounted so that it swings freely under the influence of gravity

physical pendulum (noun)	pendulum (noun)
pendulum consisting of an actual object allowed to rotate freely around a horizontal axis	an apparatus consisting of an object mounted so that it swings freely under the influence of gravity