G, in physics, a symbol relating to gravity. A capital G indicates the gravitational constant, as explained in the article GRAVITATION. A lower-case g stands for the acceleration imparted by gravity at the earth’s surface. An acceleration of 1 g is 32. 1 feet per second per second (9. 8 m/so). Fliers and astronauts may experience accelerations many times larger than 1 g. These accelerations are usually expressed in multiples of g, such as g, g, etc.
For example, when the speed of a space vehicle increases 96. Feet per second (29. 4 m/s) during a second of travel, the vehicle is said to be accelerating at 3 g’s. An astronaut in the space vehicle would experience a force, called a g force, three times as strong as the force of gravity at the earth’s surface. Great effort is required to move parts of the body against the g force produced at an acceleration of 3 g’s. Tolerance to even greater accelerations depends on the position of the individual in relation to the g force.
A person in an upright position with respect to the g force suffers temporary vision loss at about 4 g’s, and loss of unconsciousness at 5 to 8 g’s, because the amount of blood reaching the brain is reduced. A person in a lying position with respect to the g force can endure up to 20 g’s for short periods G-forces are capable of transforming stomach contents into airborne projectiles. The first drop, she begins a one-minute adventure filled with various sensations of weightlessness, heaviness, and Jerkiness.
The parts of the ride which are most responsible for these sensations of weightlessness and heaviness are the clothed loops. The explanation for the various sensations experienced on a roller coaster loop re associated with Newton’s laws of motion and the physics of circular motion. Http://physics. Steeplechases. Com/questions/43967/normal-forces-and-Ferris-wheels ;At the top of the hill/Ferris wheel, you’re momentarily at rest (in the axis parallel to the ground anyway). When the ground moves away from under you, the perceived push-back is less, hence less normal force, resulting in the feeling of relative weightlessness. As you near the bottom, your body is in motion downwards, but now the ground is pushing back to slow that motion; in other words, the normal force increases, resulting in a heavy feeling.