Gravity : History, Definition, and Formula

Overview

Have you ever wondered why you strike on the Earth instead of drifting off into space when you jump? Why do items fall to the ground when one throws or drops them in the air? The answer to all these questions lies in one concept, gravity! Now, what is gravity? Gravity is an invisible force or pulls that attracts items to each other. Gravity is what keeps humans on the Earth’s ground and causes things to fall back on the surface.

According to gravity definition, gravity exists in everything with its particular mass. Gravity is directly proportional to the weight of the objects and inversely proportional to the distance of the objects. As a result, the closer two objects are to one another, the stronger the force of attraction between them.

What is Gravity: History

The contributions of Albert Einstein and Isaac Newton best define gravity; they have dominated the evolution of gravitational theory. Newton’s fundamental theory of gravitational force reigned supreme from the publication of his Principia in 1687 until Einstein’s work in the early twentieth century. Even today, Newton’s theory suffices for even the most accurate applications. Except for a few exceptions, Einstein’s theory of general relativity predicts minor quantitative deviations from Newtonian theory.

The most important aspect of Einstein’s theory is its profound intellectual deviation from classical theory and its implications for future advances in physical cognition.

Define Gravity

What is gravity: Gravitation, often known as gravity, is the natural pull of attraction which can be implemented between all objects having mass in physics. It is one of the weakest forms of natural pull and does not influence common objects’ interior characteristics. On the contrary, due to its extensive reach and ubiquitous action, it influences the motions of celestial bodies present in this or another universe, as well as the architecture and formation of stars, constellations, and the entire cosmos.

All bodies on Earth have their particular weight or mass, or falling gravity force, directly proportional to their weight or mass, which is exerted by the Earth’s mass. Gravity definition is analysed by the velocity of that freely falling object.

According to gravity definition, gravity’s force at the Earth’s surface is approximately 9.8 metres (32 feet) per second. Thus, a particle’s speed rises by around 9.8 metres per second for every second it is in rapid decline (free-fall). The speed of a freely falling object on the moon’s surface is approximately 1.6 metres per second.

Thus to define gravity, one can say that gravity is the force that pulls items toward the centre of a planet or any other entity. The gravitational pull keeps all the planets or other celestial objects within their orbit and helps them revolve around the sun.

Curiously EnoughAll of its mass causes the gravity of the Earth. All of its mass exerts a cumulative gravitational force on all of the body’s mass. That is what grants people weight. Similarly, suppose if a person is on a planet with a lower mass than Earth, they would weigh less and have the same gravitational pull on Earth as it has on others. However, since Earth is much bigger and heavier than an ordinary individual, a normal human force has little influence on the planet.

Earth’s Gravity

Gravity plays a crucial role for humans. Humans couldn’t survive without it. Because of the gravitational force, the sun’s gravity keeps Earth in its orbit and helps it to revolve around it, thereby allowing humans to enjoy the sun’s light and warmth from a safe distance.

It keeps the environment, and the air humans need to breathe stable. The planet Earth is held together by gravity.

However, gravity does not exist everywhere on Earth. Gravity is slightly greater underground in areas with more mass than in areas with less mass. NASA employs two satellites to measure changes in Earth’s gravity. The Gravity Recovery and Climate Experiment (GRACE) mission include these spacecraft.

Gravitational Force

The gravitational force can be best explained using Newton’s Law of Universal Gravitation. According to this law, every heavy object in the cosmos attracts every other heavy object with a force that is directly related in constant proportionality to the magnitude of their weights (or masses) and inversely (oppositely) proportional to their square of the distance.

Another current way of stating the concept is that “every single point mass draws every other single point mass by force travelling down the line connecting both points.” The gravitational force is proportional to the magnitude of the sum of masses of the two products, and at the same time, it is (inversely) oppositely proportional to the square of the distance between the two-point masses.

Everyone is surrounded by gravitational force. It determines how much humans weigh or how much a football can travel when tossed before returning to the ground. The force we humans apply on Earth is equal to the gravitational force applied by Earth. The gravitational force has always been equal to the weight of an object on Earth, whether at rest, near or on Earth. However, the gravitational pull on any other foreign astronomical body, such as the Moon or Venus, is different than on Earth; for instance, if a person stands on a weighing scale, it would display their different weight on different planets.

When two things are gravitationally interlocked, their force of gravity is focused in a location, not at either centre but the system’s barycenter. The idea works similarly to a see-saw. If two people of varying weights sit on different sides of the equilibrium point, the stronger one must sit near the equilibrium point for their masses to be equalised. For example, if the bigger person weighs double as much as the weaker person, they must sit half as far away from the centre. The midpoint of mass of the see-saw is the equilibrium location, so the barycenter is the pivot point of the Moon-Earth system. 

A barycenter can be found in every structure in the galaxy and, perhaps, the cosmos. The pull and push force between the objects prevents everything in space from colliding.

Gravitational Force: Formula

The gravitational force can be best explained using Newton’s law of gravitation. As read earlier, the gravitational force determines how much we humans weigh and how far a ball can bounce before landing on the ground when shot.

As per Newton’s law of gravity, every object in the cosmos pulls every other object with pressure directly proportional to the object’s masses and inversely proportional to the square of the distance between the two objects. 

It can be expressed as follows,

F = Gm¹m²/r²

Where,

• F represents the gravitational pull or force present between two objects calculated in Newtons (N).
• The universal gravitational constant, G has a value of 6.674 10^-11 Nm²kg^-2.
• m1 represents the weight or mass of one body or particle measured in kilograms (kg).
• m2 represents the weight or mass of another body or particle measured in kilograms (kg).
• r represents the distance between the two bodies or particles measured in kilometres (km).

Conclusion

Thus gravity is felt whenever a person jumps in the air and falls back to the ground. The gravity definition drags people back to the ground. Without gravity, people would have been floating away into space, along with all other celestial objects lying in the universe. It is evident in every object that carries its masses or weights. Learning about this mysterious gravitational force will help students in drawing multiple ideas. It will help them understand the concepts or reasons to explain why a ball falls to the ground, or an apple falls downwards rather than floating in an upward direction! 

Frequently Asked Questions 

1. What is gravitational force?

Ans. The universe is full of pulls, forces and pushes. Everyone is actively trying to pull or push something, even if it’s just the ground. All these pulls, forces and pushes depend on four fundamental laws of forces in physics. These are the gravitational force, the strong force, the electromagnetic force, and the weak force.

What is gravitational force? A gravitational force is a type of force that can attract any two objects having masses. The gravitational force is a type of attractive force that always pushes or pulls masses of two objects together rather than pushing them apart. In reality, everything in the cosmos, including humans, is tugging on another object! 

2. How does gravity benefit the universe?

Ans. Gravity keeps the planets and other celestial objects in orbit around the sun and the moon around Earth. The moon’s gravitational influence draws the waters towards it, generating ocean tides. Gravity generates planets and stars by drawing the materials that make them together.

Gravitational pull applies not only to the object’s mass but also to light. Albert Einstein discovered this principle. When a person beams a flashlight skyward, the light will get somewhat redder as gravitational acceleration increases. These light changes are invisible to the naked eye, but researchers can measure them. Because black holes compress so much weight into such a compact space, their gravity is capable of preventing everything, even light, from departing.

3. Will you maintain your body weight when travelling from Argentina to Greenland?

Ans. No, it will rise. Because the gravitational acceleration is higher at the poles and less at the equatorial regions (because of Earth’s bulged oblate shape), people will feel heavier in Greenland. (Greenland is nearer the North Pole than Argentina.)