Gravitational methods

Newton’s law of gravitation states that the force (in newtons) between two pointmassesm₁, m₂ is equal to Gm₁m₂/r2 where r is the distance between the masses and G = 6.61 x 10−11 [≈(20/3)x 10−11]m3kg−1s−2. The force is one of attraction and acts along the line joining the two point masses. We say that the point mass m₂ is in a field of force (the gravitational field) due to m₁ and vice versa. Since ‘Force = Mass x Acceleration’, the acceleration of m₂ will be Gm₁/r2. Indeed, it is evident that the acceleration of any point mass due to m₁ will be Gm₁/r2 towards m₁.