Under what circumstances can a state of gravity be created on Earth?

When you fly around the Earth at high speed in a spacecraft, when the centrifugal force is equal to gravity, it is equal to a state of gravity, (as in a spaceship).

In the water, even astronauts are now in the water for weightlessness training.

A free-fall state is similar to a gravity-free state.

No! Our physics teacher stresses this issue all day long! Let's emphasize it to you

First of all, it is necessary to distinguish between gravity and gravitational force are two different concepts!

Then, you can explain it according to the concept!

Gravity is relative to the earth, which is the gravitational force of the earth on all things (it can also be understood as the gravitational force of all things on the earth, and the effect of force is mutual and always knows). When we study this problem, we think of the earth as a sphere, so its point of action is at the center of the sphere, which is the center of the earth, right? Then we can also know from the three elements of force that the force of gravitation is directed towards the center of the earth!

Secondly, gravity can be clearly known from the concept of high school textbooks, and the direction of the lead sensitive force is vertically downward!

And the relationship between gravity and gravitational force is actually that gravity is just a component of gravitational force!

This last concept may be difficult for you to understand, but remember, at this point, you can no longer think of the earth as a sphere!!

In fact, it is precisely because of the fact that when this concept is prescribed, there is a disagreement about whether or not to treat the earth as a sphere, and because these problems are avoided in the textbooks, they generally do not clearly explain the world, but only make ambiguities. That's why it eventually leads to problems like the landlord. In fact, beginners have this problem...

me，too！~

Report to the landlord, over, over!

Weightless sinks can create gravity-free conditions.

Due to the gravitational pull of the Earth, a state of true weightlessness cannot be achieved on the ground for a long time. The way people move and work in weightlessness is completely different from the way they move and work in gravity on the earth's surface. In order to complete the mission of out-of-cabin activities, astronauts must be proficient in the rules and skills of movement and operation in weightlessness.

At present, the equipment that can simulate the weightless environment has the falling tube, the falling tower, the sounding rocket, the weightless aircraft and the water tank that simulates the weightlessness training, etc., but the weightless environment simulation equipment that can carry out astronaut training is only the weightless aircraft and the simulated weightless training tank, and other simulation equipment can not carry out manned experiments because the weightless time obtained is too short, and the effective volume of the test is too small. When a weightless aircraft flies in a parabolic flight, it can produce a weightless environment for 15 to 30 seconds, and in such a short time, only astronauts can experience the weightless environment and train them in simple operation. As a result, complex out-of-cabin movements and operations can only be performed in a simulated weightlessness training tank.

Four places on Earth where gravity is almost zero.

17.What would happen without gravity on Earth? You have to jump and drink water when you drink water, and you can only suspend when you sleep.

Definitely not. Gravity is the force between two objects that attracts each other and is one of the essential properties of an object.

Any two objects will have a gravitational pull on each other.

There is always a gravitational force between two objects, i.e., the gravitational force of "all". It's just a matter of size.

The effective gravitational force of the earth is very wide, and the moon, which is 380,000 kilometers away, is still subject to the gravitational pull of the earth and revolves around the earth.

I guess you're asking about weightlessness in spaceships

The moon is still subject to the Earth's gravitational pull for 380,000 kilometers, so why is it weightless in a spacecraft of 200 kilometers?

In fact, the objects and people in the spacecraft are still subject to a very strong gravitational pull of the earth, just because when the spacecraft moves in a circle around the earth, the spacecraft generates centrifugal force, which cancels out the gravitational pull of the earth. So it's "weightlessness" and not loss of gravity.