## Weightlessness – Class 11 | Chapter – 8 | Physics Short Notes Series PDF for NEET & JEE

Weightlessness: Weightlessness is the sensation experienced by an object or person when they are in a state of free fall, where they are falling under the influence of gravity but without any external support or resistance. When an object or person is in free fall, they are essentially weightless because the force of gravity is not being opposed by any other force.

## Why Do We Feel Weightlessness?

Weightlessness can be experienced in a variety of situations, including during parabolic flights, when an aircraft follows a curved path that produces brief periods of weightlessness; during spaceflight, when an object or person is in orbit around the Earth; and during deep sea diving, when a diver is in a state of neutral buoyancy, where the buoyant force of the water is equal to the force of gravity.

In a state of weightlessness, objects and people float and move freely because there is no force of gravity pushing them down towards a surface. This can be disorienting and can cause feelings of nausea or motion sickness, as the body’s vestibular system, which is responsible for maintaining balance and orientation, is no longer being stimulated in the same way as it is on Earth.

## Why Do Astronauts Feel Weightless in Space?

Astronauts feel weightless in space because they are in a state of free fall around the Earth. The force of gravity still acts on them, but because they are in a constant state of motion, they are constantly falling towards the Earth, and this motion cancels out the effects of gravity.

On Earth, we feel the force of gravity because we are in contact with the ground, which pushes back against us with an equal and opposite force. This force is what we perceive as weight. In space, there is no ground to push back against, so there is no perceived weight.

When an object or person is in free fall, they are essentially weightless because they are falling under the influence of gravity but without any external support or resistance. This is the same reason that objects and people feel weightless on a roller coaster or during a parabolic flight.

Astronauts in orbit around the Earth are in a state of free fall because they are constantly falling towards the Earth, but they are also moving horizontally at a fast enough speed to avoid crashing into the Earth’s surface. This combination of horizontal motion and gravity causes them to continuously fall towards the Earth without actually hitting it. As a result, they experience weightlessness while in orbit.

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