What kind of velocity can get rid of the gravitational pull of the Earth? 20

Gravitational pull on Earth.

Everything within the range is affected by the gravitational pull of the earth, from humans to animals, from mountains and rocks to air. It is precisely because of gravity that the earth has an atmosphere.

Only then do they have the basic conditions for the survival of life.

The speed of kilometers per second is called the "first cosmic velocity", which keeps orbiting the Earth. If we increase the speed up to kilometers per second, this artificial satellite can travel to interplanetary space within the solar system without being affected by the Earth's attraction. If we want artificial satellites to fly out of the solar system and travel to other planets, we have to increase the speed to kilometers per second.

The speed of kilometers per second is called the "second cosmic velocity"; The speed of kilometers per second is called the "third cosmic velocity."

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Analysis: When the body reaches a speed of kilometers and seconds, it can free itself from the constraints of the earth's gravity. In the process of getting rid of the shackles of the earth, under the action of the earth's gravity, it does not fly away from the earth in a straight line, but flies in a parabola.

After breaking away from the Earth's gravitational pull, it orbits the Sun under the action of the Sun's gravitational pull. To escape the gravitational pull of the Sun and fly out of the solar system, an object must move at a speed of 1,000 seconds. It will then fly away from the Earth in a hyperbolic trajectory, and it will fly away from the Sun in a parabola relative to the Sun.

Human space activities are not just about escaping the earth. In particular, the current application spacecraft needs to fly around the Earth, that is, let the spacecraft move in a circle. We know that there must always be a force equal in magnitude to the centrifugal force and in the opposite direction acting on the spacecraft.

Here, we can take advantage of the gravitational pull of the Earth. This is because the gravitational pull of the earth on an object is exactly in the opposite direction of the centrifugal force in which the object moves in a curvilinear motion. It has been calculated that when the speed of motion of an object on the ground reaches a kilometer second, the centrifugal force generated by it is equal to the gravitational pull of the earth on it.

This velocity is known as the orbital velocity.

The speed at which the object moves in a circle around the earth is called the first cosmic velocity; The speed at which the earth flies away from the gravitational pull of the earth is called the second cosmic velocity; The speed at which the sun is free from the gravitational pull of the sun and flies out of the solar system is called the third cosmic velocity. According to the law of gravitation, the magnitude of the gravitational force between two objects is inversely proportional to the square of their distance. Therefore, the distance of an object from the center of the earth is different, and its orbital velocity (first cosmic velocity) and separation velocity (second cosmic velocity) have different values.

1.Second cosmic velocity.

2.Third, the cosmic velocity is complete.

Correct Answer: Second cosmic velocity.

If the muzzle velocity reaches the planet's escape velocity, the object will completely escape the planet's gravitational pull and fly out of the planet. The velocity at which the object needs to escape the gravitational pull of the planet is called the escape velocity. The surface of a celestial body is stared at the minimum velocity required for an object above it to break free from the gravitational pull of that object and fly into space.

For example, the Earth's breakaway velocity is kilometers and seconds (i.e., the second cosmic velocity).

When the velocity is reached, it can break away from the gravitational pull of the earth.

If an object is shot vertically upwards from the planet's surface, if its initial velocity is less than the planet's escape velocity, the object will only rise a certain distance, after which the acceleration caused by the planet's gravitational pull will eventually cause it to fall. The escape velocity of the Earth is.

As shown in the figure below: the earth is approximately a sphere, simplified to a sphere...

Then the object with mass m on the ground is equal to the magnitude of attraction f of the earth, and the direction points to the center of the earth o1.

Assuming that M is located at M position on the ground, since M rotates with the earth, M will move in a circle around the latitude line with O2 as the center of the circle, and the required centripetal force F1 is provided by the component of F, the closer to the north and south poles, the smaller the radius of the circle centered on O2, it can be seen from F1=M R, the smaller F1, the size of F remains the same, F1 decreases, F2 is getting closer and closer to F (i.e., F2 gradually increases) and F2 is the usual gravity, then it can be known from gravity G=mg=F2:

g is getting bigger.

Gravity: The force of mutual attraction between all objects with mass. This force exerted by the Earth on other objects is called gravity.

The gravitational pull experienced by other objects is in any direction. According to Newton's law of gravitation, there is a gravitational force between any two substances that have mass.

According to the law of gravitation, there is an attractive force between any two objects. This includes between the Earth and other objects. Its size is directly proportional to the product of the masses of the two and inversely proportional to the distance.

Since the mass of the earth is very large, and the distance between the objects on the surface and the earth is small, there will be a large gravitational pull.

The Earth itself has quite a large mass, so it also exhibits gravitational pull on any objects around the Earth. Take a cup as an example, the earth shows gravitational pull on the cup at any time, and the cup also shows gravitational pull on the earth.

The mass of the earth is too large, and the gravitational force on the cup is very large relative to its own mass, and the acceleration is relatively large, so the cup is attracted to it, and the direction is towards the center of the earth, and this force is gravity.