“Gravity is the force of attraction between all objects in the universe.”
Gravitation refers to the natural force of attraction existing between all objects in the universe. This force, known as gravity, is responsible for keeping planets in orbit around stars and stars in orbit around the centre of galaxies.
Imagine two objects, such as a basketball and a bowling ball, placed near each other. Due to the force of gravity, the basketball and the bowling ball are both drawn towards each other, as if they were being pulled together.
Gravitation is the force of attraction between all objects in the universe.
The force of gravity between two objects depends on their masses and the distance between them. The larger the mass of an object, the greater its gravitational pull. The farther apart two objects are, the weaker the gravitational pull between them.
In 1666, a famous story in the history of science occurred. Isaac Newton was sitting in his mother’s garden when he saw an apple fall from a tree. This experience inspired him to investigate the concept of gravity. Newton was able to uncover the reason why objects fall. He also found out that gravity causes the planets to revolve around the sun and makes the moon and satellites orbit around the earth in a specific manner.
Newton’s Law of Gravitation is one of the most crucial laws of physics that explains how two objects are attracted to each other. This law was discovered by Sir Isaac Newton in 1687 and explained the behaviour of all objects in space, including planets and stars.
“Every object in the universe attracts every other object with a force proportional to the product of their masses and inversely proportional to the square of the distance between them.”
Mathematically, it can be represented as:
F ∝ m1 m2 ___________(i)
F∝1/r2___________(ii)
Combining equation (i) and (ii);
F ∝ m1m2 / r2
F = Gm1m2 / r2
Where F is the force of attraction, G is the gravitational constant, m1 and m2 are the masses of the objects, and r is the distance between the centres of the objects. This law governs the behaviour of the entire universe and helps us understand how celestial bodies move and interact with each other.
The constant “G” in Newton’s Law of Gravitation is known as the gravitational constant. It is a number that represents the strength of the force of gravity between two objects. The value of G has been measured and determined through experiments, and its value is constant for all objects in the universe.
The value of G is approximately 6.67×10-11 Nm2/kg2.
These examples show how the law of gravitation can be used to calculate the force of gravity between any two objects in the universe. The formula remains the same for all objects, no matter how large or small they are and how far apart they are from each other.
To understand this law, let us consider two bodies of masses m1 and m2. The distance between their centres is r.
According to the statement, the force of attraction between two bodies is directly proportional to the product of their masses. Therefore,
\(F \propto m_1 m_2\)
The gravitational force of attraction is inversely proportional to the square of the distance between the centres of the masses of the bodies.
Therefore,
\(F \propto \frac{1}{r^2}\)
Combining equation (i) and equation (ii)
\(F \propto \frac{m_1 m_2}{r^2}\)
Replacing proportionality with a constant
\(F=G\frac{m_1m_2}{r^2}\)