G-forces, or gravitational forces, refer to the acceleration experienced by an object due to gravity or changes in motion. They are measured in units of "g," where 1 g is equivalent to the acceleration due to Earth's gravity, approximately 9.81 meters per second squared. When an object accelerates, such as during a roller coaster ride or in a car making a sharp turn, passengers feel a force pushing them against their seats. These forces can be positive or negative, depending on the direction of acceleration. Positive G-forces occur when an object accelerates forward, pushing occupants down into their seats, while negative G-forces happen during rapid deceleration or upward motion, causing a feeling of weightlessness. High G-forces can affect the body, leading to potential risks like G-induced Loss Of Consciousness (GLOC) in extreme situations.