2. Gravitational Field Strength

Definitions

Gravitational Field Strength

• Force per unit mass experienced by a small test mass placed at a point in the field

Field Lines

• Arrows show direction of the force
• Line density increases with the strength of the field
• Field is the strongest where the field lines are the closest

Neutral Point

• The point at which the force 1 object is equal to the force of another

Derivations

Using

$$F = \dfrac{GMm}{r^2}$$

we can calculate the acceleration using $F = ma$

$$ma = \dfrac{GMm}{r^2}, \quad \quad a = \dfrac{GM}{r^2}$$

we denote $a$ as $g$ for acceleration due to gravity

$$g = \dfrac{GM}{r^2}$$

 

Field Lines

Notice for gravitation, the field lines alway point inwards

 

Neutral Point

Useful Equations

$$F = \dfrac{GMm}{r^2}, \quad \quad g = \dfrac{GM}{r^2}$$