The reference collection is a great place to begin your research. These short relevant articles will give the basic understanding you need to formulate a good research question.
Physics branches out over many different subject areas. If you want to browse either the reference (main floor) or regular (upstairs) collections to find material, I would suggest that you look in the following sections:
QB 1-991 - Astronomy
QC 1-75 - General Physics
QC 81-114 - Weights and measures
QC 120-168.85 - Mechanics
QC 170-197 - Atomic physics
QC 221-246 - Acoustics
QC 251-338.5 - Heat
QC 350-467 - Optics. Light
QC 474-496.9 - Radiation
QC 501-766 - Electricity and magnetism
QC 770-798 - Nuclear and particle physics
QC 801-999 - Geophysics