# Force of gravity and gravitational field – problems and solutions

1. Two objects m_{1} and m_{2} each with a mass of 6 kg and 9 kg separated by a distance of 5 cm. Object m_{3 }= 1 kg is placed between the two. If the gravitational force experienced by m_{3 }= 0 then the distance m_{3} from m1 is …

Gravitational force = 0 if F_{13} = F_{23}.

a = -1, b = -20, c = 50

Use quadratic formula:

The results cannot be negative. So x = r_{13} = distance m_{3} and m_{1} = 2.25 cm.

2. Two objects A and B are 60 cm apart. Mass A is 24 kg and mass B is 10 kg. Where is the location of a point that has a strong gravitational field equal to zero?

Gravitational field = 0 if g_{A} = g_{B}.

a = 7

b = -1440

c = 43200

Use quadratic formula:

x = r_{A} = 169.25 cm or

x = r_{A} = 36.46 cm