IB Physics A.5.3 Lorentz Transformations Key Definitions

Length contraction is the phenomenon where an object in motion appears shorter along the direction of motion to a stationary observer.

The Lorentz transformations relate the coordinates of an event in one inertial frame to those in another moving at a constant velocity relative to the first.

Proper length ($L_0$) is the length of an object measured in the frame where the object is at rest.

Proper time ($\Delta t_0$) is the time interval between two events measured in the frame where the events occur at the same location.

Time dilation is the phenomenon where time passes more slowly for an observer in motion relative to a stationary observer.