Newton's Law of Universal Gravitation
Contents
Key Stage 3
Meaning
Newton's Universe Theory of Gravitation is a scientific theory developed by Sir Isaac Newton that explains that the planets are held in orbit around The Sun by gravity.
About Newton's Universal Theory of Gravitation
- Before Newton scientists had many different ideas about how planets were held in orbit around The Sun. Some thought they were held by magnetism and others thought the planets were held in invisible crystal spheres around The Sun.
- Newton was the first to realise that the force which pulls objects to the ground on Earth might be the same as the force that keeps planets orbiting The Sun and The Moon orbiting the Earth.
Key Stage 4
Meaning
Newton's Universe Theory of Gravitation is a scientific theory developed by Sir Isaac Newton that explains that the planets are held in orbit around The Sun by gravity.
About Newton's Universal Theory of Gravitation
- Before Newton scientists had many different ideas about how planets were held in orbit around The Sun. Some thought they were held by magnetism and others thought the planets were held in invisible crystal spheres around The Sun.
- Newton was the first to realise that the force which pulls objects to the ground on Earth might be the same as the force that keeps planets orbiting The Sun and The Moon orbiting the Earth.
Key Stage 5
Meaning
Newton's Law of Universal Gravitation states that the force between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
About Newton's Law of Universal Gravitation
- Newton's Law of Universal Gravitation can be used to calculate the magnitude of the force acting between two masses.
- Newton's Law of Universal Gravitation has a similar form to Coulomb's Law in that both are given with a constant multiplied by a product of some physical property (charge and mass) and inversely proportional to the square of the distance between particles.
Equation
\(F=-G \dfrac{m_1m_2}{r^2}\)
Where;
\(F\) = The force acting between the charged particles
\(G\) = The Gravitational Constant (\(6.67\times10^{-11}\))
\(m_1\) = The mass of one object.
\(m_2\) = The mass of the second object.
\(r\) = The distance between the centre of mass of each object.
The definition can be derived from the equation by considering;
\(-G\) is a constant so the left hand side and right hand side are proportional.
\(m_1m_2\) is the product of the masses.
\(\dfrac{1}{r^2}\) is the the inverse of the square of the distance.
Therefore;
\(F\propto\dfrac{m_1m_2}{r^2}\)