Investigate the factors that affect the gravitational field strength

The gravitational field strength at a point is the gravitational force exerted per unit mass placed at that point.

Hence it is defined as gravitational field strength , where

  • Fg = Gravitational force
  • m = mass of the object placed at that point.

As the gravitational force is given by , the gravitational force experienced by an object of mass m, due to a planet of mass M is given by gravitational force

we can get field strength around the planet experienced by an object of mass m as field strength

Note : We know that , force. Thus we can see that the acceleration due to gravity and the gravitational field strength are the same units.

Thus we can see that gravitational field strength

  • is inversely proportional to the square of the radial distance from the center of the object which gives rise to the gravitational field: square of the distance between their centers
  • is directly proportional to the mass of the object which gives rise to the gravitational field: directly proportional to the mass of the object

Thus gravitational field, where g denotes gravitational field strength

 
 

Extract from Physics Stage 6 Syllabus © 2017 NSW Education Standards Authority (NESA)