Value of Gravitational Constant - Unit, Application, FAQs

G, the Newtonian gravitational constant, is one of nature's most fundamental constants, yet scientists still don't know its exact value of gravitational constant. Although Isaac Newton introduced the gravitational constant in his popular work Philosophiae Naturalis Principia Mathematica in 1687, it was not until 1798 that the constant was observed in a real experiment. Don't be surprised if this happens. In physics, it's usually like this. In most cases, mathematical predictions come before experimental proofs. Anyway, Henry Cavendish, an English physicist, was the first to successfully quantify it, using an extremely sensitive torsion balance to measure the very small force between two lead masses. Although there have been more accurate measurements after Cavendish, the gains in value of gravitational constants (i.e., being able to achieve value of gravitational constants closer to Newton's G).

It is the proportionality constant in Newton's law, which connects the gravitational force value between two bodies to the product of their masses and the inverse square of their distance. It quantifies the relationship between the geometry of space-time and the energy-momentum tensor in the Einstein field equations.

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What is the Gravitational constant?

The gravitational constant is the physical constant denoted by G, which appears in Newton's law of gravitation's equation. Sir Isaac Newton, an English mathematician, calculated the behaviour of gravity. He discovered that the gravitational force value between two objects is proportional to the product of their masses and inversely proportional to the square of their separation.

According to Newton's law, any two objects with mass m1 and m2 (in kilogrammes) and a distance r (in metre) between their centres would have a gravitational force value F (in Newton) acting on them. The following is a description of gravitational force value:

Fm1m2

F1/r2

Fm1m2r2

F=Gm1m2r2

The approximate value of the gravitational constant is, G = 6.67408 × 10-11 N m2 Kg-2

The value of the gravitational constant of the gravitational constant remains unchanged on the moon, Mars, or anywhere else in the universe, making it an invariant entity.

How to Measure the Gravitational constant?

. Hundreds of years and a global collaboration of scientists later, there is still no explanation for how it works. Scientists are also frustrated because they haven't been able to compute the exact force despite working on it for almost a century.

Researchers in modern times have come extremely near with their findings; however, the current known value of gravitational constant for the universal gravitation constant is 6.67408 10^{-11}m^3 kg^-1 s^-2. In their innovative concept, Chinese researchers have updated the old method of determining gravitational constant using a torsion pendulum experiment. This original approach was created by Henry Cavendish in 1798, and it has been changed numerous times since then to improve accuracy.

In the first way, the researchers created a metal-coated silica plate that was suspended in the air by a wire. The gravitational attraction is provided by the two steel balls. The force of gravity was calculated by determining how much the wire was twisted.

The second method was similar to the first, but the plate was suspended from a spinning turntable, which held the wire in place. The gravitational force value was measured using this method by observing the spin of the turntable.

By include seismic properties in both approaches; the researchers were able to avoid influence from adjacent objects and disturbances.

Gravity Constant:

Metres per second squared (m/s2) or Newtons per kilogramme (N/kg or N.Kg-1) are the SI units for acceleration. The gravitational acceleration near the Earth's surface is about 9.81 m/s2, which means that air resistance isn't a factor. Every time an object free-falls, its speed increases by 9.81 metres per second.

SI unit of gravitational constant:

Per kilogramme square, 6.67 x 10 -11newton metres square (N x m 2 x kg -2). The value of quantity g in the law of gravitation of the constant is constant throughout our solar system and galaxy, as well as in nearby galaxies.

F=G ( m1.m2)/ R2 is the gravitational force value.

Newton is the unit of force (N)

Kg is a unit of mass.

R is in meters in the unit of measurement.

Unit of G:

G=Nm2Kg-2

Also Read:

• NCERT Solutions for Class 11 Physics Chapter 8 Gravitation
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Applications:

1. Sir Isaac Newton's Universal Law of Gravity was the first to investigate the Gravitational constant.

2. In this theory of relativity, Einstein expanded on this.

3. This empirical constant is solely used in the research of gravitational impacts in a variety of disciplines.

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NCERT Physics Notes:

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