Question

Weightlessness experienced while orbiting the earth, in spaceships, is the result of which of the following: acceleration, inertia, zero gravity or centre of gravity. Pls explain.It is not zero gravity

Answer 1

Long periods of weightlessness occur onspacecraftoutside a planet's atmosphere, provided no propulsion is applied and the vehicle is not rotating. Weightlessness does not occur when a spacecraft is firing its engines or when re-entering the atmosphere, even if the resultant acceleration is constant. The thrust provided by the engines acts at the surface of the rocket nozzle rather than acting uniformly on the spacecraft, and is transmitted through the structure of the spacecraft via compressive and tensile forces to the objects or people inside. Weightlessness in anorbitingspacecraft is physically identical to free-fall, with the difference that gravitational acceleration causes a net change in thedirection, rather than themagnitude, of the spacecraft'svelocity. This is because the accelerationvectoris perpendicular to the velocity vector. In typical free-fall, the acceleration of gravity acts along the direction of an object's velocity, linearly increasing itsspeedas it falls toward the Earth, or slowing it down if it is moving away from the Earth. In the case of an orbiting spacecraft, which has a velocity vector largelyperpendicularto the force of gravity, gravitational acceleration does not produce a net change in the object's speed, but instead actscentripetally, to constantly "turn" the spacecraft's velocity as it moves around the Earth. Because the acceleration vector turns along with the velocity vector, they remain perpendicular to each other. Without this change in the direction of its velocity vector, the spacecraft would move in a straight line, leaving the Earth altogether.