## Gravity

Gravity or Gravitation is a phenomenon in which all things with energy or mass, including galaxies, stars, planets, and lights, are attracted. Gravity gives weight to the mass on earth. The gravitational attraction of the gaseous matter present in the universe caused it to begin coalescing and form stars and group these stars into a galaxy. Because of gravity only, many large-scale structures are present in the universe. Gravity rance is unlimited but as objects get further away its effects become increasingly weaker. Out of the four fundamental forces, gravity is said to be the weakest force. It has no significant influence at the level of subatomic particles. At the microscopic scale, it is known as the dominant interaction, and it is the cause of the formation of the shape and trajectory of astronomical bodies. In the universes, the earliest trace of gravity was possibly in quantum gravity, supergravity, and ordinary time and space, possibly from the primitive state.

### History

Albert Einstein most accurately describes gravity in 1915 by his theory of relativity wherein he explained that gravity is not as a force, it’s just a consequence of the curvature of spacetime caused by the distribution of mass unevenly. Newton’s law of universal gravitation well defines gravity for most applications, which describes gravity as a force, due to which, any two bodies attract each other with a proportional force to the product of their masses and square of the distance between them. Out of four fundamental interactions of physics, gravity is the weakest one, it is almost 1038 times weaker than the strong interaction, 1036 times weaker than the electromagnetic force, and 1029 times weaker than the weak interaction. At the level of subatomic particles, it has no significant influence. On the contrary, it is the dominant interaction at the macroscopic scale, and due to this shape and trajectory (orbit) of astronomical bodies are formed.

### Gravitational Field Intensity

Gravitational field intensity is the strength of a gravitational field which is applied on a unit test mass.

\[Eg=\frac{F}{m}\]

A gravitational force’s intensity depends upon the source mass and the distance of unit test mass from the source mass.

The unit of gravitational field intensity is N/Kg.

To explain the influence on a massive body extending into the space around itself, which produces a force on another massive body, a gravitational field model is used as a term used in Physics.

Out of four fundamental interactions of physics, gravity is the weakest one, it is almost 1038 times weaker than the strong interaction, 1036 times weaker than the electromagnetic force, and 1029 times weaker than the weak interaction. At the level of subatomic particles, it has no significant influence. On the contrary, it is the dominant interaction at the macroscopic scale, and due to this shape and trajectory (orbit) of astronomical bodies are formed.

The identification of the Gravitational field intensity dimensional formula of the acceleration.

Principle of superposition extends to gravitational field intensities as,

X = X1 + X2 + . . . . . . . + Xn and many more terms.

Where X1, X2, . . . . . Xn is the gravitational field intensities at a point due to n particles in a system.

Mass is always distributed in two different ways:

Discrete mass distribution \[\bar{E}\] = \[\sum_{i=1}^{n}\] E\[_{i}\]

Continuous mass distribution \[\bar{E}\] = \[\int_{i}^{f}\] dE

### The Gravitational Intensity of a Point Mass X

Consider a point mass X and the gravitational intensity at a distance ‘y’ from it.

\[Eg =\frac{-GX}{y^2}\widehat{r}\]

Gravitational field intensity due to a solid sphere

The gravitational field intensity inside the solid sphere

is given by Eg

\[=\frac{GMr}{R^3}\]

That is Eg is directly proportional to r

### Applications

During the last few decades, we can see the remarkable progress that has been made in improving the gravitational models of the Earth and the terrestrial planets. These models’ determination has been established using a wide variety of very different measurement solutions and types and techniques. The measurement types for measuring the Earth’s potential field can be divided into many but few of them are as satellite tracking measurements, surface gravity measurements, and satellite altimeter measurements; planetary gravity fields are determined exclusively from tracking data from the source. Gravity fields established by the accurate error estimates are used to support a huge variety of applications, including the application of orbit determination of spacecraft, a variety of geophysical investigations, oceanographic investigations using satellite altimetry, and the definition of a unique datum. The latter becomes increasingly important and that is because of its implications in the level of the sea which is studied and in the determination of orthometric heights and height differences from GPS positioning without the need for leveling the particular level.

This paper in recent models will briefly review the progress made in gravity models, a spectrum of different kinds of applications of global gravity field models, and even describe their ability to meet the current requirements. In addition, in the solid earth ocean-atmospheric system, characteristics of the gravity field’s temporal variations will be reviewed concerning obtaining a better understanding of important geophysical ongoing processes.

### Characteristics of Inertial Mass

Following are the characteristics of inertial mass:

The inertia of a body is measured by its inertial mass.The amount of matter in the body is proportional to the inertial mass.

The inertia of a given body depends on the size,shape and state of the body.

Inertial mass is not dependent on the body's temperature.

Inertial mass of a body is not affected by the presence or absence of any other bodies around it.

Inertial mass always follows the simple algebraic law of addition when combined and the simple algebraic law of subtraction when separated or removed.

Inertial mass of a substance is conserved in a chemical reaction.

If the speed of the body is comparable to the speed of light, only then the inertia of the body will be affected.

### Gravitational Mass

This is described by the gravitational force, which asserts that each pair of objects has a gravitational force, which is provided by

\[F = G\frac{ m1 m2}{r2}\]

G is the universal gravitational constant, m1 and m2 are the masses of the two objects, and r is their distance. This effectively defines an object's gravitational mass.

As it turns out, these two masses are exactly the same in terms of mass. The equivalence of these two masses is also why all objects on Earth fall at the same pace.

The sole difference between inertial and gravitational mass is the method used to calculate it.

## FAQs on Gravitational Field Intensity

**1. What Factors Produce the Gravitational Field Lines?**

The field lines or the gravitational field lines are the gravitational forces exerted per unit mass on a very small scale at a particular point in the field. The like forces it is a vector quantity, a point mass M at the origin produces the gravitational field.

**2. How Do We Represent Gravitational Field Lines Represented?**

The gravitational field lines are directly shown as the force would act on an object placed at that point in space. The magnitude of the gravitational lines is by the spacing of lines, the closer the lines are towards each other, the magnitude is higher. The gravitational field lines vary slightly at the earth's surface.

**3. Explain How the Gravitational Field Lines Converge?**

The field lines or the gravitation field line are always pointed towards the central mass, therefore G is larger when lines are close together, and they are far apart the smaller. The strength of the gravitational field intensity that is close to the earth can be considered the uniform as the earth’s surface is relatively flat at a point.

**4. How Can Gravity be Generated?**

Gravity can be created by using a centripetal force. The centripetal force directed towards the center of the turn is required for any objects to move in a circular path. In the rotating space context, the space station is the normal force provided by the spacecraft hull that acts as centripetal force.

**5. What is Gravitational Force?**

The gravitational force is explained using Newton's Law of Universal Gravitation. According to this law, every heavy particle in the universe attracts every other heavy particle with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them. This broad physical law was formed via inductive findings. 'Every point mass attracts every other point mass by a force-directed down the line crossing both points,' says another, more current version of the rule. The gravitational force is equal to the product of the two masses and inversely proportional to the square of the distance between them.'

**6. What are examples of gravity?**

Gravity is the force that pushes two bodies together, as we learned in this article. Here are some instances of gravity:

The gravitational force that exists between the Sun and the Earth.

The force that causes the Moon to orbit the Earth in a spherical orbit.

The power of the Moon causes the tides that occur in the ocean.

The force that holds all of the gasses in the Sun together.

The force exerted on us causes us to walk on the ground rather than float in mid-air.

**7. How to determine the gravitational force and inertial mass of a body?**

The force of gravity of an unknown mass is compared to the force of gravity of a known mass to determine its gravitational mass. This is usually accomplished using a balancing scale. The beauty of this system is that the masses will always balance out regardless of where you are on the globe since the gravitational acceleration on each item will be the same. Due to the steep gradient of the gravitational field around supermassive objects such as black holes and neutron stars, this breaks down.

Using a known force to an unknown mass and measuring the acceleration, and applying Newton's Second Law, m = F/a, yields inertial mass. This provides you a mass value that is as exact as your measurements. When astronauts need to be weighed in space, they sit in a special chair to determine their inertial mass.

**8. What is gravitational potential energy?**

The amount of work done in displacing a body of mass (m) into the gravitational influence of a source mass (M) is stored in the form of potential energy when it is moved from infinity to a point inside the gravitational influence of a source mass (M) without accelerating it. Gravitational potential energy is the term for this. The letter Ug is used to represent it. We know that a body's potential energy is defined as the energy stored in the body at that particular location. When external forces modify the position of the body, the change in potential energy is equal to the amount of work done on the body by the forces.

**9. Where can I find notes and questions on Gravitational Field Intensity?**

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