Geostationary satellites, near Earth satellites with objects on Earth

For this kind of topic, it is necessary to distinguish between objects: one is an orbiting satellite off the earth, and the other is an object on the ground.

First of all, it is necessary to have common sense that the linear velocity of objects on the ground is much smaller than that of satellites, because it takes a considerable speed to get rid of the gravitational constraints of the earth (the starting speed is greater than or equal to 7900 km s), and if the ground objects can catch up with the speed of satellites, they will have already flown into the sky, which is obviously unreasonable (the linear velocity at the Earth's equator is only.

Second, for satellites, v= gm r is obtained by the formula gmm (r 2) = mv 2 r, which shows that the linear velocity of the satellite is inversely proportional to the square root of the orbital radius, so the farther away the satellite is, the smaller its linear velocity (and angular velocity). Even so, the velocity of the geostationary orbiting satellite is still greater than the orbital velocity of the ground object, which is obtained by v=w·r, and the linear velocity is proportional to the radius when the angular velocity is the same. So v2>v3>v1, a, b are all wrong.

Thirdly, when comparing the acceleration, for the satellite by the formula gmm (r 2) = ma, the centripetal acceleration here is obtained a=gm (r 2), then the closer the acceleration is, the greater the acceleration, so a2 > a3

Then for the synchronous orbit satellite and the near-earth object, when the angular velocity is the same as a=w 2·r, the acceleration is proportional to the orbital radius, and we know that a3>a1, so a2>a3>a1, so d is correct.

Note that the hills are on Earth, so the period should be the same as that of the Q satellite. The smaller the radius, the greater the acceleration, the greater the velocity This is said when gravity acts as a centripetal force and does not apply to ground objects. So v2> v3> v1, a2>a3>a1

I didn't understand the third question. But you should get the idea.

The velocity of e is synchronized with the rotation of the Earth, p has to overcome the larger gravitational pull, q receives the least influence and the acceleration is maximum.

A geostationary satellite is an artificial Earth satellite with the same period of operation and rotation as the Earth, which remains relatively stationary with the Earth and is always located directly above the equator.

Near-Earth satellites (NEOS) are satellites whose orbits are near the Earth's surface, and the orbital radius can be approximated when calculating.

1. Similarities between geostationary satellites and near-Earth satellites.

1.Both are moving in a uniform circular motion around the Earth's axis, and the centripetal force is related to the Earth's gravitational pull;

2.Geostationary satellites have the same period as objects on the equator: t = 24 h;

3.Near-Earth satellites have the same orbital radius as objects at the equator: r=r0 (r0 is the radius of the Earth).

2. Differences between geostationary satellites and near-Earth satellites.

1.The orbital radius of the synchronous satellite is different: the orbital radius of the synchronous satellite = r0 + h, h is the height of the synchronous satellite from the ground, about 36,000 kilometers, and the orbital radius of the near-earth satellite and the equatorial object is approximately the same, both are r0.

2.The centripetal force is different: the centripetal force of geostationary satellites and near-Earth satellites orbiting the Earth is provided entirely by the Earth's gravitational pull towards them, the centripetal force of an equatorial object is provided by one component of gravity, and the other component of gravitational force provides the gravitational force of an equatorial object.

3.The centripetal acceleration wheel combustion search degree is different.

4.The cycle is different.

5.The line speed is different.

6.The angular velocity is different.

Geosynchronous satellites are often used in communications, meteorology, radio and television, missile warning, data relay, etc., to achieve continuous work in the same area. Geosynchronous satellites are divided into geostationary satellites, inclined geostationary satellites, and polar geosynchronous satellites. Geosynchronous satellites are artificial satellites that operate from west to east in geosynchronous orbit.

The orbital period is the same as the Earth's rotation period and is 1 sidereal day, which is 23 hours, 56 minutes and 4 seconds. <

Geosynchronous satellites are often used in communications, meteorology, radio and television, missile warning, data relay, etc., to achieve continuous work in the same area. Geosynchronous satellites are divided into geostationary satellites, oblique geostationary satellites, and polar geostationary satellites. Geosynchronous satellites are artificial buried satellites that operate from west to east in geosynchronous orbit.

Its orbital period is the same as that of the Earth, which is 1 sidereal day, i.e. 23 hours, 56 minutes and 4 seconds, and is about 35,786 km above the ground and 42,164 km from the center of the Earth. Geosynchronous satellites are often used in communications, meteorology, navigation, and military intelligence search.

Characteristics of near-Earth satellites: Ideally, satellites that are close to the Earth's surface, with a radius of rotation equal to the Earth's radius.

Characteristics of artificial satellites: the launch speed is not necessarily, it may be a near-earth satellite, it may be a synchronous satellite, it may be a satellite of another planet. Depends on the launch speed.

Characteristics of geostationary satellites: From outside the earth, the satellite rotates together with the earth, and the angular velocity is the same as the angular velocity of the earth's rotation. Remain relatively stationary with the Earth (in the same direction, at equal velocity).

The relationship between the three: Near-Earth satellites and geostationary satellites are both types of artificial satellites. There can be many kinds of artificial satellites, and if the launch speed is appropriate, they can become near-Earth satellites or geostationary satellites, and of course they can also become other types of satellites.

1. The cycle is different.

A period of 85 minutes for near-Earth satellites and 24 hours for geostationary satellites.

2. The relative speed is different.

Near-Earth satellites are moving relative to people on the ground, and geostationary satellites are synchronous and stationary relative to the ground.

3. The height is different.

The operating altitude of the near-Earth satellite is equivalent to the radius of the earth, and the geostationary satellite is operating at an altitude of 35,786 kilometers.

1. The track radius is different

1) The orbital radius of the geostationary satellite = r0+h, h is the height of the geostationary satellite from the ground, which is about 36,000 kilometers.

2) Near-Earth satellites have approximately the same orbital radius as equatorial objects, both r0.

2. The centripetal force is different

1) The centripetal force of geostationary satellites and near-Earth satellites orbiting the Earth is provided entirely by the Earth's gravitational force towards them, the centripetal force of an equatorial object is provided by one component of the gravitational force, and the other component of the gravitational force provides the rebound force of the equatorial object.

3. The height is different.

1) The operating altitude of the near-Earth satellite is equivalent to the radius of the Earth.

2) The altitude of the geostationary satellite movement is 35,786 km.

4. The operating cycle of the satellite is different

1) Near-Earth satellite: Near-Earth satellite's geostationary satellite = object on the equator, which is t = 85min.

2) Geostationary satellites: Geostationary satellites have the same period as planetary rotation. The period of near-Earth satellite operation is t=85min, which is the minimum period of all satellites.

Encyclopedia - Geostationary satellites.

The difference between geostationary satellites and near-Earth satellites is mainly reflected in their orbital characteristics.

Geostationary satellites are located in geosynchronous orbit at the same speed as the Earth's rotation, so they always maintain coverage of each location on Earth. Due to its high lifting degree and small communication delay, it is often used in telecommunications, radio, television and other fields.

Near-Earth satellites are located in the Earth's near-earth orbit and are faster than the Earth's rotation, so they can only cover one area of the Earth. The high response has a large communication delay due to its low altitude, but it can provide high-resolution ground images due to its low altitude. It is often used in meteorology, remote sensing, aviation, aerospace and other fields.

1. The period and gravitational acceleration are different.

Objects at the equator: the period is 24 hours, and the acceleration due to gravity is about g.

Near-Earth satellite: The acceleration is about g.

Geostationary satellites: the period is 24 hours.

2. The speed is different.

Speed: Equatorial Objects "Geostationary Satellites" Near-Earth Satellites.

3. The acceleration is different.

Acceleration: Geostationary satellite "Near-Earth satellite = equatorial object.

In middle school physics, this question is often used to test centripetal acceleration and centripetal force.

First of all, it is said that the object that rotates with the earth at the equator, it rotates with the earth, so of course there is a centripetal force and centripetal acceleration. But it is important to note that the centripetal force of this object is the gravitational pull of the earth minus the supporting force of the earth towards the object. Hence the centripetal force is less than the gravitational force (gravitational force).

Also note that the gravitational acceleration of the object at this time is equal to the gravitational acceleration of the Earth minus the centripetal acceleration.

Objects in low-earth orbit. The radius of the low earth orbit is approximately equal to the radius of the earth, so it experiences the same gravitational acceleration as the ground object, but it does not experience the support force of the ground, so the centripetal acceleration is equal to the gravitational acceleration.

Objects on geostationary orbits (geostationary orbits are not the same as synchronous orbits, which are often confused in textbooks, but this difference is negligible for middle school students). Geostationary orbit is characterized by angular velocity equal to the angular velocity of the Earth's rotation. But like low-Earth orbit, gravitational acceleration is equal to centripetal acceleration.

And since its orbital radius is greater than the radius of the Earth, the centripetal acceleration is greater than the centripetal acceleration of the ground object.