What is weightlessness? Why is it weightless?

A state in which an object moves freely in a gravitational field without exhibiting weight or lightness, also known as zero gravity. Weightlessness is sometimes referred to in terms of zero-gravity and microgravity environments. To be precise, it is weightless when the acceleration is straight downward.

The phenomenon of weightlessness occurs mainly in orbit or in space or in some other abnormal conditions (far from a planet or a heavy object).

Definition: Refers to an object that loses the action of the gravitational field.

Gravity: A component of the Earth's gravitational pull on an object.

Main phenomenon: The pressure of the object on the support is less than the gravitational force.

Classification of weightlessness: complete weightlessness and non-complete weightlessness.

In life, overweight and weightlessness are very common, for example, when people are in the elevator, when the elevator accelerates up, they feel that the pressure on the soles of the feet of the elevator increases, which is the phenomenon of overweight.

In order to reduce the pressure on the bridge, the bridge generally causes a convex shape, so that the car has a downward acceleration when crossing the bridge and the pressure on the bridge is reduced, when the car passes through the sunken road surface, due to the vertical upward acceleration and the phenomenon of overweight, often make the car tire burst due to the high pressure.

Due to gravity, on the ground, the balls made with modern technology are not absolutely spherical, which is one of the important reasons for the wear of the bearings, if in the spacecraft can be made of absolutely spherical balls, and the astronaut in the spacecraft due to complete weightlessness, so his diet, life methods must be very different from the ground. Overweight and weightlessness are two opposite concepts, so I'll explain them to you together.

There is an object and we assume the mass m. Now, this object is moving vertically upwards (i.e., in the direction of leaving the Earth) with acceleration a. Obviously, because of this motion, the pressure n on the horizontal support surface (or the tension t on the vertical overhang) is greater than the weight of the object itself, which should be equal to m(g+a).

This phenomenon is called overweight. We often say that the object is overweight.

Similarly, now, if the object moves vertically downward (i.e., towards the Earth) with acceleration a, the pressure n (or tension t) above will be less than the weight of the object itself, which should be equal to m(g-a). This phenomenon is called weightlessness. We often say that the object is weightless.

If a = g, then the object is in fact in free fall, the pressure n (or tension t) is zero, and we say that the object is completely weightless

For example, an object in a satellite that moves in a uniform circular motion around the Earth has zero pressure on the satellite's floor because its vertical downward acceleration a is the gravitational acceleration g at the position of the satellite.

Of course, in daily life, we can also experience overweight and weightlessness. For example, in an elevator, we can go through the process of being overweight and weightless. When the elevator starts to ascend, we are overweight at this point as we have an upward acceleration along with the elevator.

On the contrary, when the elevator starts to descend, we are weightless at this point as we have a downward acceleration along with the elevator. If the elevator breaks down, we will fall down with the elevator. We must be completely weightless at this point.

However, of course, we would rather not have such an experience.

Weightlessness. Weightlessness means that the object loses the effect of the gravitational field, and when the object is in a weightless state, the object will not be affected by any external gravitational field except for its own gravity.

Gravity is a component of the Earth's gravitational pull (almost equal in magnitude) to an object. The magnitude of the gravitational force is directly proportional to the mass and inversely proportional to the square of the distance. In the case of a celestial body with a certain mass, the farther away an object is from it, the smaller its gravitational pull is, i.e., the smaller the gravitational force, and at a sufficient distance, its gravitational pull is negligible.

The so-called weightlessness means that the gravity is zero, that is, zero gravity.

The so-called gravitational force is the gravitational pull of the celestial body on the object.

The magnitude of the gravitational force is directly proportional to the mass and inversely proportional to the square of the distance.

In the case of a celestial body with a certain mass, the farther away an object is from it, the smaller its gravitational pull is, i.e., the smaller the gravitational force, and at a sufficient distance, its gravitational pull is negligible. But there is more than one celestial body in the universe, and the gravitational pull of many celestial bodies forms a gravitational field. Therefore, space will not be a weightless environment.

Of course, in local areas, such as in the Earth-January system, only the gravitational pull of the Earth and the Moon is considered, and at certain points between the Earth and the Moon, the gravitational pull of the Earth and the Moon cancels each other out, and the gravitational force is zero. There is also a gravitational equilibrium point between the sun and the earth.

Manned spacecraft flying around the earth are generally only a few hundred kilometers from the ground, and the space there will certainly not be a zero-gravity environment, even if the spacecraft flying around the earth at an altitude of 36,000 kilometers, the space around it will not be zero gravity, but only light gravity, that is, gravity is lighter (smaller) than the surface of the earth.

The orbital control thruster ignition, the movement of the astronauts, the rotation of the motors, and the slight aerodynamic drag on the spacecraft can all cause the spacecraft to produce micro-acceleration. Therefore, the weightlessness in which the spacecraft is located is strictly a state of microgravity. The rotation of the spacecraft destroys this state.

In weightlessness, the human body and other objects can float with very little force. Long-term weightlessness can cause the physiological effects of weightlessness in people. Weightlessness has a great impact on the equipment on the spacecraft that is related to fluid flow.

The weightlessness of aerospace can be used to carry out some scientific research and material processing that are difficult or impossible to achieve on the ground, such as the growth of high-purity large single crystals, the manufacture of ultra-pure metals and superconducting alloys, and the preparation of special biological drugs. Weightlessness provides favorable conditions for assembling structurally large spacecraft in space.

Weightlessness is when part of the gravitational force of an object is used to produce centripetal acceleration (such as the astronauts of Shenzhou 6 revolving around the Earth) or other vertical downward acceleration (such as in an elevator or helicopter that decelerates down), so that the original effect of gravity is weakened (such as a decrease in the pull on a rope, a decrease in pressure on another object, etc.).

Weightlessness is a phenomenon in which the pressure of an object on a support (or the pull on a suspended object) is less than the gravitational force on which the object is subjected. Therefore, the weight of weightlessness is not the gravity of the real object, but the object can be pressed against the floor by gravity, and the pressure is equal to gravity, but this pressure is reduced, so the object is weightless.

Weightlessness is the phenomenon that the weight of the object is less than its actual weight when the gravity is less than g = kg per square meter of gravitational acceleration, which is generally due to downward acceleration or entering the space of gravitational acceleration g = kg per square meter

For example: falling from the sky, taking an elevator, and going into space.

In weightlessness, the apparent weight (if the object is placed on the scale, the measured value is the apparent weight) is less than the actual weight of the object (actual weight).

When the upward deceleration movement or downward acceleration movement will occur, weightlessness will occur You can feel a slight sense of weightlessness when you get off the elevator. ~

Quite simply, nothing gives you an upward force in the direction of antigravity, that is, in general, a person is in the vertical direction and does not experience any external force (including orthogonal decomposition).

out of the external force, nor can it be vertically upward), and the vertical downward force can have.

Practical words, such as:

1.Skydiving.

Mobilization, before holding an umbrella in the air, is basically completely weightless.

Target. 2.Geostationary satellites.

is completely weightless.

3.A person who can't think of it, the moment he jumps off the building, is completely weightless.

Wait a minute. In summary, total weightlessness refers to the reaction force that completely loses gravity.

The effect of the effect, that is, the complete absence of an external force capable of fighting gravity.

In addition, the reason why this state is called weightlessness is because when people feel gravity, they actually feel the reaction force of gravity, and when the reaction force is gone (or greatly reduced), then people feel the same as losing gravity.

Gravity may still be there, but we don't feel it.

That is to say, complete weightlessness does not mean that there is no gravity, but if there is no gravity, then it must be completely weightless, for example, in the far reaches of space.