Theoretical physics concentrates on developing the theory and mathematics of these laws, while applied physics focuses attention on the application of the principles of physics to practical problems. ...Theoretical physics concentrates on developing the theory and mathematics of these laws, while applied physics focuses attention on the application of the principles of physics to practical problems. These include astrophysics (physics of astronomy), geophysics (physics of geology), biophysics (physics of biology), chemical physics (physics of chemistry), and mathematical physics (mathematical theories related to physics).
F=ma : If a force F is applied to a body of mass m, it will accelerate with acceleration a=F/m. If body 1 acts on body 2 with a force F, then body 2 will act back on body 1 with...F=ma : If a force F is applied to a body of mass m, it will accelerate with acceleration a=F/m. If body 1 acts on body 2 with a force F, then body 2 will act back on body 1 with force F (equal in magnitude and opposite in direction).