The Eötvös effect is the change in perceived gravitational force caused by the change in centrifugal acceleration resulting from eastbound or westbound velocity. When moving eastbound, the object's angular velocity is increased (in addition to the earth's rotation), and thus the centrifugal force also increases, causing a perceived reduction in gravitational force. Here, is the relative acceleration is the rotation rate of the Earth is the velocity in latitudinal direction (east-west) is the latitude where the measurements are taken. is the velocity in longitudinal direction (north-south)