  In this paper, the local inertial coordinate system is calculated through
coordinate transformations from laboratory coordinate system. We derived the
same free falling equations as those in General Relativity. However, the
definitions of second and higher order covariant derivatives are different. Our
results are different from the classic view of the principle of equivalence,
and suggest that all the laws of physics in gravitational field can be given by
doing coordinate transformations from local inertial coordinate system to lab
coordinate system.
