GRAVITATIONAL FIELD

i.   Gravitational force between two masses (Newton’s law of universal gravitation)

Isaac Newton established that every two particles of matter separated by a distance attract each other with a force.

Newton”s law of universal gravitation – states that every two particles of matter attract each other with a force which is directly proportional to the product of their mases and inversely proportional to the square of their distance of separation. 

          F = (Gm₁m₂)/r²

where     F = force of attraction

m₁ and m₂ = two masses

           G = gravitational constant

              = 6.673 x 10-11 N m2/kg2

EXAMPLE

Determine the force of gravitational attraction between the earth (m = 5.98 x 1024 kg) and a 70-kg physics student if the student is standing at sea level, a distance of 6.38 x 106 m from earth’s center.

“G” as a universal constant

The gravitational constant (G) is a physical universal constant used in calculating the gravitational attraction between two objects. the value of “G” is 6.673 x 10-11 N m2/kg2

        G is rather anomalous among the other constants of physics because the mass M of any celestrial object cannot be determined independently of the gravitational attraction that it exerts.

Gravitational potential