The astral motion and the gravitational force provide the centripetal force, why can t the gravitati

When an object moves in a circular motion, the direction of velocity is constantly changing. This requires the action of force. The centripetal force plays a role in changing the direction of velocity.

Therefore, the gravitational pull of the sun on the earth changes the direction of the earth's rotational speed. If the gravitational force is greater than the required centripetal force, the earth will move closer to the sun, which is called centripetal motion, and if the gravitational force is less than the required centripetal force, it will do centrifugal motion. Only when the gravitational force is just equal to the centripetal force can the earth revolve steadily around the sun.

It's very messy, and it needs to be sorted out, "the gravitational force received by the earth is directed towards the sun, that is, the gravitational force received by the earth does not need to act as a centripetal force" There is a problem with this sentence, first understand this: the gravitational force received by the earth is directed towards the sun, which can provide centripetal force, and the earth needs this centripetal force to do circular motion.

The wonderful thing about the problem is that the sun is indeed "pulling" the earth, but it cannot "pull" the earth closer to the sun, because this "pull" (which is actually gravitational force) is just enough to constantly change the direction of the earth's motion and make the earth move around the sun.

At any given moment, the direction of the earth's motion is along the tangent direction of the circular orbit, and if there is no sun "pulling", the earth will move along the tangent direction of the circular orbit, getting farther and farther away from the sun.

Halo, gravity is gravity, and pull is elastic! They are not forces of the same nature, and the earth has a velocity so that it is not attracted by the sun (and cannot be said to be pulled over).

Because gravity causes the celestial bodies next to them to move in a circular motion around the center, and doing circular motion to maintain the balance of various forces, gravitational force always makes the stars revolve. In our increasingly economically developed society, not only has science and technology advanced, but our vision has also shifted from the earth to space. Throughout the history of Chinese science, there have been a group of very good scientists who have studied the movements of these celestial bodies.

Most of these celestial motions are related to physics. The famous gravitational force was discovered by Newton, and it was an apple that discovered the problem. According to the concept of gravitational force, we know that there is a gravitational force between any two objects.

It is not felt on Earth, but it is noticeable in space. Relative to the solar system, most of the planets revolve around the solar system, and the force that makes the planets rotate is mainly gravity. I have the following views on the question of why gravity always makes the stars revolve.

1. There is a gravitational attraction between the planets and the sun, and if they don't go around, they will be attracted to it.

Anyone who has studied mechanics in junior high school and high school knows that there is a gravitational force in any object, and the gravitational force between the planets and the sun is very large, depending on their mass. The sun is as large as 1.3 million Earths relative to Earth. Therefore, if there is no other equilibrium in the gravitational force, then the earth will be attracted to it, so the earth will revolve around the sun, and the centrifugal force generated will cancel out the gravitational force, so that the balance can be maintained.

2. The gravitational force and the centrifugal force of the planets rotate in balance, so that the stars orbit.

Anyone who has learned circular motion knows that the circular motion of an object will produce a centrifugal force, if there is no force pulling inward, then the object will move outward, relative to the celestial bodies in space, this pulling force is the gravitational force, so the gravitational force and the centrifugal force of the planet rotation are balanced, so that the star will rotate.

3. Gravitational force will only be generated.

Before Newton discovered gravitation, others had little concept of gravity or even gravitation, and Newton developed the three laws of mechanics in gravitation, which are still widely used today.

Because gravitational forces are mutually exclusive, some different molecular forces may be generated, so there will be a star orbiting.

This is because the rotation of the stars is in a circular motion, and this keeps the centrifugal force in balance, and it is also affected by the motion of the celestial bodies. So there will be periodic changes.

This is because different stars have different gravitational pulls on each other, which is why this phenomenon is formed, and it also means that different planets are affected by the stars and rotate.

This is because some centrifugal motions in circular motion balance the gravitational force.

First, the law of gravitation: all objects in the universe are attracted to each other The gravitational pull between two objects is directly proportional to the product of their masses and inversely proportional to the square of their distances

From our observations on Earth, all moving celestial bodies have an attraction that leans towards their center, attracting not only their own parts, but also other celestial bodies within their sphere of action. Therefore, the effect of gravity is reciprocal, not only does the Sun and Moon affect the shape and motion of the Earth, but the Earth also affects the Sun and the Moon, and even Mercury, Venus, Mars, and Jupiter have an effect on the Earth's motion.

Second, any celestial body that is moving in a simple straight line will continue to move in a straight line until it is subjected to other forces to cause it to move along an elliptical orbit, circumference, or complex curve.

Third, following the basic law of the motion of celestial bodies - the gravitational force is equal to the centripetal force of circular motion, which is still a basic method of dealing with physical problems, and the closer the object is to the center of attraction, the greater its attraction will be.

Once this relationship is known, astronomers can easily solve the laws of celestial motion. ”

Since the birth of the universe, all the best fragments have not only expanded in all directions, but according to the law of gravitation, those who are close will attract and collide with each other to form a new combination. All the fragments are in high velocity, and the result of attracting each other is that when the gravitational and antigravitational forces are equal, the small fragments move in a circle around the large fragments; The gravitational force is greater than the anti-gravitational force, it will be closer and closer, on the contrary, it will be farther and farther, the gravitational force and the anti-gravitational force formed by long-term evolution [equal], it seems that the planets revolve around the sun, in fact, absolute equality is impossible, either closer to the sun or away from the sun, however, these changes, for us, are a long time, it is said that the moon is getting farther and farther away from the earth. The centripetal force of circular motion is not provided by anyone, it is the centripetal force and centrifugal force formed by the combined force of small fragments (planets) and large fragments (sun).

If there is no centripetal force, according to the law of inertia, the planet has long since left the sun and does not know how to run up, and similarly, without centrifugal force, the planet is close to the sun, and it has long been torn apart by the sun. The stable relationship between the sun and the eight planets, the solar system, was formed by a long-term evolution of 5 billion years.

Solar system.

First of all, let's explain what gravity, gravitational force and centripetal force are.

For example, on Earth, gravitational force = gravity + centripetal force (under the parallelogram theorem), and it is important to understand that gravity and centripetal force are the two components of gravitational force.

1.For example, if you are at 30° north latitude, then you receive a centripetal force perpendicular to the earth's axis and a gravitational force perpendicular to the ground on the ground, gravitational force = gravity + 4 centripetal force.

2.For example, if you are at the North Pole, then you should theoretically also receive centripetal force and gravity, but because you are on the earth's axis at this time, you do not receive the centripetal force provided by the earth's rotation, it can also be said that the centripetal force at this time is 0, but the gravity at this time has reached the maximum, and gravity is equal to the centripetal force at this time, although it is still in line with gravitational force = gravity + centripetal force, but it is more appropriate to say that gravitational force = gravity + 0.

3.For example, if you are at the equator, the centripetal force is at its maximum, and the gravitational force is 0, which is the opposite in the second case, i.e. gravitational force = 0 + centripetal force.

Next, let's talk about space, take the moon and the earth as examples, because the moon receives the earth's gravitational force in space, and because gravitational force = gravity + centripetal force, the moon almost revolves around the earth's equatorial plane, so the centripetal force reaches the maximum, and the gravity force is zero. So gravitational force = 0 + centripetal force. So gravitational force is centripetal force.

It must be stated here that due to various complex factors in space, the Moon does not actually revolve exactly around the Earth's equatorial plane, but these are beyond my ability and I can only help here. If you still don't understand, you can add QQ, and the voice is more efficient.

The gravitational force is the resultant force of the centripetal force and the gravitational force, and when the gravitational force completely provides the centripetal force, the other component force is zero, i.e., the gravitational force is zero.

Follow-up question: Why does gravity provide all the centripetal force?

Answer: The centripetal force is provided by gravity.

Answer: The satellite moves around the celestial body, the distance is far from the comparison section, and the centripetal force is provided by the gravitational force.

Follow-up question: gravitational force will provide centripetal force and gravity, it is possible that gravitational force will also provide gravity at the same time as centripetal force, why is it only said that centripetal force is provided.

Follow-up question: Is it not subject to gravity if it is far away?

Follow-up: Gravity is the Earth's grip on objects on Earth, not celestial bodies.