You can't "do" physics just like you can't "do" chemistry, biology, geology etc. For the mathematical part of physics, equations in physics range from very basic algebra skills to multi variable calculus.
Wikipedia gives you a good definition and a very large list of areas. There's also the "Simple English" wikipedia. They give a very short and good definition for Physics. See...
The main branches of classical physics include: Classical Mechanics Electromagnetism Optics Thermodynamics As well as many other sub-branches like hydrodynamics, aerodynamics, etc. In modern physics,...
Molecular physics looks at the subatomic world. It looks at particles such as quarks, Leptons and a major study by CERN in Europe is searching for a particle known as the higgs boson. These...