# Universal Gravitation Constant - HELP

• John231
In summary, the constant of universal gravitation, denoted by G, is a universal constant that relates the magnitude of the gravitational force between two objects to their masses and the distance between them. It is not the force itself, but rather the proportionality constant that helps calculate the force using Newton's law of gravitation.

#### John231

Universal Gravitation Constant - HELP!

Hello, I'm a little confused...

What is the difference between the "Constant of Universal Gravitation" and the "Gravitational Force"? I know that there is a radius between two or more objects like the Earth and the Moon and bla bla bla... But the thing that I want to know is the "Constant of Universal Gravitation". Is it the force between the two objects??

I would be grateful if someone could answer my question!

Thanks!

Force between moon Earth and blah blah is

## F=\frac{Gm1m2}{d2} ##

F is the force. G is the universal gravitational constant

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John231 said:
What is the difference between the "Constant of Universal Gravitation" and the "Gravitational Force"?
Force is variable (something you compute) depending on the masses and the distance between the masses. The constant is, well a constant.

John231 said:
But the thing that I want to know is the "Constant of Universal Gravitation". Is it the force between the two objects??
No, it's a universal constant, G ≈ 6.67 x 10-11 Nm2/kg2. See Gravity (HyperPhysics) and/or Gravitational constant.

John231 said:
Hello, I'm a little confused...

What is the difference between the "Constant of Universal Gravitation" and the "Gravitational Force"? I know that there is a radius between two or more objects like the Earth and the Moon and bla bla bla... But the thing that I want to know is the "Constant of Universal Gravitation". Is it the force between the two objects??

I would be grateful if someone could answer my question!

Thanks!
Newton's law of gravitation essentially says that gravitational force between two bodies is proportional to the product of their masses divided by the square of the separation between their centres of mass (mM/r^2). G is the proportionality constant relating the magnitude of the force to mM/r^2. In math terms, G is equal to the Force divided by (mM/r^2).

AM

## 1. What is the Universal Gravitation Constant (G)?

The Universal Gravitation Constant, also known as Newton's Constant, is a fundamental physical constant that determines the strength of the gravitational force between two objects. It is denoted by the letter G and has a value of approximately 6.67 x 10^-11 Nm^2/kg^2.

## 2. How was the value of G determined?

The value of G was first calculated by Sir Isaac Newton in his law of universal gravitation, which states that the force of attraction between two objects is directly proportional to their masses and inversely proportional to the square of the distance between them. Since then, scientists have conducted numerous experiments to measure G, with the most accurate value being determined by the Cavendish experiment in 1798.

## 3. Does the value of G change?

No, the value of G is considered to be a constant and does not change. However, there have been some discrepancies in experimental measurements of G, leading to ongoing research and debate about its true value. Some scientists believe that G may vary slightly depending on various factors such as the composition of the Earth's core and the distance between the objects being measured.

## 4. What are the units of G?

The units of G are Nm^2/kg^2, which can also be written as m^3kg^-1s^-2. This reflects the force of attraction between two masses (Nm), divided by the product of their masses (kg^2) and the square of the distance between them (m^2).

## 5. What is the significance of G in the study of gravity?

G is a crucial constant in the study of gravity, as it helps us understand and calculate the gravitational force between any two objects in the universe. Without G, we would not be able to accurately determine the strength of the gravitational pull between planets, stars, and other celestial bodies. It also plays a key role in the laws of motion and the understanding of the formation and structure of the universe.