Difference between Gravitation and Gravity

The gravity and the force of Gravitation are very similar terms that are commonly used in Physics. Generally, people consider these two as the same term. Although these two sound alike, there is a difference between the two. Gravitation is the force acting between two bodies While, gravity is the force between an object and the earth’s surface. In this article, we will discover topics related to both gravitation and gravity, their differences, the difference between gravity and mass, the difference between gravity and gravitational potential energy. Let's start by understanding the Gravitational force.

Gravitation and gravity are two very commonly used words in Physics that sound similar but the concepts are not the same. Although both the terms are related to forces acting between two bodies, there's a lot more than just that! Let's understand the individual concepts of the two terms before delving into their differences.

What is Gravity?

Gravity is the force of attraction acting between an object and the earth's surface. The earth has a pulling force towards itself, thereby attracting an object towards itself. Just like us humans on the earth's surface, other objects like the Moon is pulled towards it by a force (F) which is directly proportional to the mass (M) of the object, ie,

F ∝ M

It is obvious that to make it an equation a constant term is multiplied to the right-hand side, and in this case, the constant term happens to be the acceleration due to gravity (g). Therefore,

F = M×g

The constant value of g is 9.8 m/s² and for ease of calculation, it is rounded off as 10 m/s². 

Note: The value of g is not uniform on the earth everywhere.

What is Gravitational Force?

The gravitational force is the universal force of attraction between two bodies placed at a distance in the universe. It is one of the most fundamental forces in the universe. 

According to Newton's universal law of gravitation, the force of attraction between any two bodies is directly proportional to the product of their masses and is inversely proportional to the square of the distance between them, i.e.,

\[F \propto \frac{(m_{1} \times m_{2})}{r^{2}}\]

where F is the gravitational force of attraction between two bodies

m₁ and m₂ are the masses of the two bodies, and

r² is the distance between the centre points of the two bodies.

Now, again to equate F to the right-hand side, a constant has to be multiplied. Here, 

\[F = \frac{G.(m_{1}m_{2})}{r^{2}}\]

Here, G is the universal constant whose value is 6.67 X 10^-11 Nm²/Kg². It is very obvious from the small value that the gravitational force between two objects that are very far away is very weak.

Note: The value of gravitational force is constant throughout the universe.

Gravitational force is a natural phenomenon that occurs between two distant objects placed in the universe that causes them to move. We know that everybody in this universe moves under the influence of some force. So, the force which is acting between the two bodies in the universe is termed as the gravitational force. 

(Image will be uploaded soon)

In the above figure, two bodies are separated by a distance of x and the masses of the two objects are m₁ and m₂ respectively. So, the force which acts between the two bodies is directly proportional to their masses and inversely proportional to the distance between them:

\[F \propto \frac{M_{1} M_{2}}{x^{2}}\]

• Where F is force

• M1 is the mass of the first body.

• M2 is the mass of the second body.

The above equation can be further simplified as:

\[F = \frac{G M_{1} M_{2}}{x^{2}}\]

Where G is a universal gravitational constant whose value is 6.67 X 10-11 Nm2/Kg2.

The G is a universal constant hence its value is the same all over the universe. The force experienced by the bodies depends on their masses as well as the distance between them. So, from the above equation, it can be concluded that the force between the bodies will be higher when the bodies are of large masses and the force will be very low in case the two bodies are separated at a very large distance with respect to each other.

Force of Gravity

Gravity is a natural phenomenon that acts between the earth surface and the object placed in the universe. The force of gravity can be defined as the force acting between the earth and an object present near it. Gravity is directly related to earth and the object present nearby it. As we know that the mass of the earth is extremely huge, and it is to be noted that the body of higher mass attracts the body with lower mass. Thus, it is said that the force of gravity is attractive in nature, as the earth attracts the body present near to it.

F = Mg

Where F is the force,

M is the mass of an object,

g is the acceleration due to gravity and its value is calculated as 9.8 m/s² and is taken as 10m/s² for calculation purposes. But this acceleration due to gravity is not a universal constant and its value shows variation from place to place. It is to be noted that the gravitational force is extremely small compared to the force of gravity. So, it can be said that two objects on the surface of the earth will not attract or repel each other easily. While earth can attract any falling body towards it easily. This is the reason why objects fall on the ground. Now, let's understand the difference between the gravitational force and the force of gravity.

Difference between Gravitation and Gravity

Now comes the points that set gravitation and gravity apart:

1.  While gravitation is the force of attraction between two bodies in the universe,  gravity is the force of attraction between some objects and the Earth's surface in particular.

2. The value of G is universally constant but that cannot be said for the value of g which varies on different points on the earth.

3. The force of gravitation is directly proportional to the masses of both the objects as well as is inversely proportional to the distance between the objects but in the case of gravity, the force of gravity is directly proportional to only the mass of the object and not of the earth.

4. The force of gravitation is a lot weaker than the force of gravity.

5. The gravitational force can be either attractive or repulsive but the force of gravity is only attractive in nature.

The term Gravitation is said to be the force that is acting between two bodies. On the other hand, gravity is the force that is occurring between an object and the earth surface.

The force of Gravitation is also said to be representing a force that is directly proportional to the product of the masses of two objects and is inversely proportional to the square of the distance between them. Usually, gravity is being considered as the natural property due to which the objects are said to be attracted towards earth. It is said that gravity plays a major role in sustaining life on earth. This is due to the fact that the term gravitational pull acts between the earth, the sun and the atmosphere is kept on our planet earth. Hence, it is the reason behind the air that we need to breathe for our survival. Not only this, but it also helps us to be at a safe distance from the star and sun.

In our universe, each and every object attracts the other with a certain amount of force. The large distance of separation is one of the main reasons for the weak nature of the force of attraction.

• The gases in the sun are held together due to the force of gravity.

• Gravity is also a responsible force for water to rest at the bottom of a glass and hover over at the top of the glass.

• The force of attraction acting between the earth surface and the moon causes tides in the ocean. This is also the result of gravity.

• The force of Gravity causes the moon to revolve around the earth.

Gravity has the same effect on every object. If we drop an iron rod and a feather, they both will fall at the same speed. Due to the external effect like air resistance on gravity, it might seem that the iron rod falls at a greater speed. But, if we drop them in a vacuum, they would fall at the same time. The Gravity of an object is directly proportional to the mass of that object. It is one of the weakest known forces in nature.

As the two terms are often a bit confusing, sometimes these two terms are misinterpreted and people consider both as the same. 

However Various Factors that Exist differentiates Gravitation from Gravity

1. The major difference between gravitation and gravity is that gravitational force occurs between two different or the same objects. While the force of gravity acts between the earth surface and any object.

2. The force of gravitation acting between two objects is quite weaker as compared to the force of gravity.

3. The Gravitational force can either be attractive or repulsive depending on the direction of movement. But, the force of gravity is only attractive, as the object is very small in mass compared to the mass of earth. Thus the object gets attracted to the earth surface.

4. The gravitational force is a universal force, whereas the force of gravity is a derived one and it may vary from one place to another.

5. While solving numerically the gravitational force acting between two objects requires the masses of both the bodies to be known while calculating force. On the other hand, in the case of determining the force of gravity, the mass of only the object needs to be determined.

Mass is a measure of how much matter an object has, on the other hand, weight is a measure of how strongly gravity pulls that matter. 

Difference between Gravity and Gravitational Potential Energy

Gravity is defined as a force that attracts a body towards the centre of the earth or other physical body having mass. The force of gravity is the weakest type of fundamental force in nature. Still, it holds the entire solar system and galaxies together. The speed of free fall is consistent over the planet earth. This speed is said to be computed as 9.8 metres per second.

Gravitational potential, on the other hand, at any point in a gravitational field is the work done in bringing a unit mass from infinity to that point. Gravitational potential determines the direction of motion of a body in the gravitational field of another body and the gravitational potential energy of a particle at any point can be measured by the work done by moving the particle from infinity to that point. Gravitational potential energy is equal to the product of potential at the point due to the body multiplied by the mass of the particle.

How is Gravity Important for Us?

It is due to gravity that the atmosphere on earth is kept and the moon is the natural satellite of the earth which in turn affects tides and ebbs on the earth's surface. We can also safely walk on earth without having to worry about flying away because of the force of gravity towards the earth.

Conclusion

So, from the above discussion, it can be concluded that gravitation and gravity are almost the same in a manner that both are specified by the force acting between two bodies. It can be easily noted that the force between two objects situated at some distance will always be gravitational. If one of the objects is the earth then it will be the force of gravity between them.