You may have heard different versions of this before:
Chemistry is the 'why' behind psychology...
Physics is the 'why' behind chemistry...
Mathematics is the 'why' behind physics...
Philosophy is the 'why' behind math...
Other heirarchies try to place physics as somewhere in between engineering and pure math.
I prefer to think of it this way:
Science literally means 'stuff that can be known.' As opposed to what, I wonder?
Gradually, we've carved off little chunks of 'science' and given them names:
botany: study of all plants
ornithology: study of all birds
neurology: study of the brain
chemistry: study of chemical interactions
Physics is, briefly, everything that's left!
So while AP Chemistry deals with 'the study of chemicals,' physics will deal with everything that moves, uses energy, produces light, reflects light, attracts or repels other things, or affects the temperature of its surroundings. This includes a comprehensive study of electrons, molecules, cellular membranes, mosquitoes, cows (typically of the spherical, frictionless variety), elephants, continents, planets, stars, and spiral arms of galaxies, among other things.
I hope you have a good instructor; if you do you'll fall in love with the subject.
P