Gravitational Fields and Forces

Gravity is simply an attractive force that exists between any two masses - yes, even you and your mate sitting next to you! The bigger the masses and the closer they are, the stronger this pull becomes.

Newton's law of gravitation gives us the mathematical relationship: gravitational force is proportional to the product of both masses and inversely proportional to the square of the distance between them. This means doubling the distance quarters the force, whilst doubling a mass doubles the force.

Field lines are brilliant visual tools that show you which way a smaller mass would move if placed in the field. The density of these lines tells you about the gravitational field strength - think of it as how many newtons of force each kilogram of mass experiences.

Gravitational potential is the work needed to bring 1kg from infinitely far away to a specific point. It's always negative (since gravity does the work for you when bringing masses together) and becomes zero only at infinite distance. Equipotential lines connect points of equal potential, and here's the clever bit - no work is done when moving along these lines, just like walking along a contour line on a mountain doesn't change your height.

Key insight: Field lines are always perpendicular to equipotential lines, and closer spacing means stronger gravitational effects.