Physics is the branch of physical sciences which mainly deals with energy.

The branches of physics are
* Astrophysics 
Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties (luminosity, density, temperature and chemical composition) of astronomical objects such as stars, galaxies, and the interstellar medium, as well as their interactions. 
* Atomic and molecular physics 
The study of the structure and characteristics of atoms and molecules. 
* Biophysics 
The science of the application of the laws of physics to life processes. 
* Condensed-matter (solid-state) physics 
The study of the physical properties of solids, such as electrical, dielectric, elastic, and thermal properties, and their understanding in terms of fundamental physical laws. 
* Cosmology 
The study of the universe as a whole, of the contents, structure, and evolution of the universe from the beginning of time to the future. 
* Geophysics 
the study of the physical characteristics and properties of the earth; including geodesy, seismology, meteorology, oceanography, atmospheric electricity, terrestrial magnetism, and tidal phenomena. 
* Mechanics 
the branch of physics concerned with the motion of bodies in a frame of reference. 
* Statistical Mechanics 
The discipline that attempts to relate the properties of macroscopic systems to their atomic and molecular constituents. 
* Theoretical physics 
Theoretical physics attempts to understand the world by making a model of reality, used for rationalizing, explaining, and predicting physical phenomena through a “physical theory”. 
* Thermodynamics 
The study of the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics. 

There are many sub branches of physics too. 

Branches of mechanics: 

1) Classical Mechanics 2) Quantum Mechanics