5.7.2 Gravitational Field Lines

• The direction of a gravitational field is represented by gravitational field lines
  • The direction shows the direction of force
  • Equivalently, they show the direction of acceleration of a test mass in the field

• The gravitational field lines around a point mass are radially inwards
• The gravitational field lines of a uniform field, where the field strength is the same at all points, is represented by equally spaced parallel lines
  • For example, the fields lines on the Earth’s surface

Gravitational field lines for a point mass and a uniform gravitational field

• Radial fields are considered non-uniform fields
  • The gravitational field strength g is different depending on how far you are from the centre

• Parallel field lines on the Earth’s surface are considered a uniform field
  • The gravitational field strength g is the same throughout