Newton’s Law of Gravitation — A/L Physics

Gravitational Force A fundamental attractive force that exists between any two objects with mass. Every particle of matter in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres. This force acts along the line joining the centres of the two masses. For example, the Earth pulls a falling apple toward its centre, and the apple pulls the Earth upward with an equal force.

Newton’s Law of Universal Gravitation The magnitude of the gravitational force between two point masses is given by F = G (m₁ m₂)/(r²) . Here, G is the universal gravitational constant ( 6.67 × 10⁻¹1 N m² kg⁻² ), m₁ and m₂ are the masses, and r is the centre-to-centre separation. The law applies strictly to point masses or spherically symmetric objects (like planets and stars) where the distance is measured from their centres. For example, the force between the Earth and the Moon can be calculated using their masses and the Earth-Moon distance.