G-force in the context of "Ultracentrifuges"

Weightlessness is the complete or near-complete absence of the sensation of weight, i.e., zero apparent weight. It is also termed zero g-force, or zero-g (named after the g-force) or, incorrectly, zero gravity.

Weight is a measurement of the force on an object at rest in a relatively strong gravitational field (such as on the surface of the Earth). These weight-sensations originate from contact with supporting floors, seats, beds, scales, and the like. A sensation of weight is also produced, even when the gravitational field is zero, when contact forces act upon and overcome a body's inertia by mechanical, non-gravitational forces- such as in a centrifuge, a rotating space station, or within an accelerating vehicle.

Space Medicine is a subspecialty of Emergency Medicine (Fellowship Training Pathway) which evolved from the Aerospace Medicine specialty. Space Medicine is dedicated to the prevention and treatment of medical conditions that would limit success in space operations. Space medicine focuses specifically on prevention, acute care, emergency medicine, wilderness medicine, hyper/hypobaric medicine in order to provide medical care of astronauts and spaceflight participants. The spaceflight environment poses many unique stressors to the human body, including G forces, microgravity, unusual atmospheres such as low pressure or high carbon dioxide, and space radiation. Space medicine applies space physiology, preventive medicine, primary care, emergency medicine, acute care medicine, austere medicine, public health, and toxicology to prevent and treat medical problems in space. This expertise is additionally used to inform vehicle systems design to minimize the risk to human health and performance while meeting mission objectives.

Astronautical hygiene is the application of science and technology to the prevention or control of exposure to the hazards that may cause astronaut ill health. Both these sciences work together to ensure that astronauts work in a safe environment. Medical consequences such as possible visual impairment and bone loss have been associated with human spaceflight.

Tilt-A-Whirl is a flat ride designed for commercial use at amusement parks, fairs, and carnivals. The ride consists of a number of cars which rotate freely while moving in a circle. As the cars revolve, the floor of the ride undulates so that the cars rise and fall as the ride spins. The offset weight of the riders causes each car to rotate. The riders experience varying levels of g-force from the spinning of the car, and the rotation of the ride itself. It is similar to a Waltzer, which is used in Europe. The rides are manufactured by Larson International of Plainview, Texas.

Cerebral circulation is the movement of blood through a network of cerebral arteries and veins supplying the brain. The rate of cerebral blood flow in an adult human is typically 750 milliliters per minute, or about 15% of cardiac output. Arteries deliver oxygenated blood, glucose and other nutrients to the brain. Veins carry "used or spent" blood back to the heart, to remove carbon dioxide, lactic acid, and other metabolic products. The neurovascular unit regulates cerebral blood flow so that activated neurons can be supplied with energy in the right amount and at the right time. Because the brain would quickly suffer damage from any stoppage in blood supply, the cerebral circulatory system has safeguards including autoregulation of the blood vessels. The failure of these safeguards may result in a stroke. The volume of blood in circulation is called the cerebral blood flow. Sudden intense accelerations change the gravitational forces perceived by bodies and can severely impair cerebral circulation and normal functions to the point of becoming serious life-threatening conditions.

The following description is based on idealized human cerebral circulation. The pattern of circulation and its nomenclature vary between organisms.

Weightlessness is the complete or near-complete absence of the sensation of weight, i.e., zero apparent weight. It is also termed zero g-force, or zero-g (named after the g-force) or, misleadingly, zero gravity.

Weight is a measurement of the force on an object at rest in a relatively strong gravitational field (such as on the surface of the Earth). These weight-sensations originate from contact with supporting floors, seats, beds, scales, and the like. A sensation of weight is also produced, even when the gravitational field is zero, when contact forces act upon and overcome a body's inertia by mechanical, non-gravitational forces- such as in a centrifuge, a rotating space station, or within an accelerating vehicle.

A ballistospore or ballistoconidia is a spore that is discharged into the air from a living being, usually a species of fungus. With fungi, most types of basidiospores formed on basidia are discharged into the air from the tips of sterigmata. At least 30 thousand species of mushrooms, basidiomycete yeasts, and other fungal groups may discharge ballistospores, sometimes at initial accelerations exceeding 10 thousand times g.

A safety harness is a form of protective equipment designed to safeguard the user from injury or death from falling. The core item of a fall arrest system, the harness is usually fabricated from rope, braided wire cable, or synthetic webbing. It is attached securely to a stationary object directly by a locking device or indirectly via a rope, cable, or webbing and one or more locking devices. Some safety harnesses are used in combination with a shock-absorbing lanyard, which is used to regulate deceleration and thereby prevent a serious G-force injury when the end of the rope is reached.

An unrelated use with a materially different arresting mechanism is bungee jumping. Though they share certain similar attributes, a safety harness is not to be confused with a climbing harness used for mountaineering, rock climbing, and climbing gyms. Specialized harnesses for animal rescue or transfer, as from a dock to a vessel, are also made.

The standard acceleration of gravity or standard acceleration of free fall, often called simply standard gravity, is the nominal gravitational acceleration of an object in a vacuum near the surface of the Earth. It is a constant defined by standard as 9.80665 m/s (about 32.17405 ft/s), denoted typically by ɡ₀ (sometimes also ɡ_n, ɡ_e, or simply ɡ). This value was established by the third General Conference on Weights and Measures (1901, CR 70) and used to define the standard weight of an object as the product of its mass and this nominal acceleration. The acceleration of a body near the surface of the Earth is due to the combined effects of gravity and centrifugal acceleration from the rotation of the Earth (but the latter is small enough to be negligible for most purposes); the total (the apparent gravity) is about 0.5% greater at the poles than at the Equator.

Although the symbol ɡ is sometimes used for standard gravity, ɡ (without a suffix) can also mean the local acceleration due to local gravity and centrifugal acceleration, which varies depending on one's position on Earth (see Earth's gravity). The symbol ɡ should not be confused with G, the gravitational constant, or g, the symbol for gram. The ɡ is also used as a unit for any form of acceleration, with the value defined as above (see also: g-force).