Question

Two charges of `-3 C` and `-1 C` are positioned on a line at points `-1` and `4`, respectively. What is the net force on a charge of `1 C` at `2`?

Answer 1

`F = 9.0 xx 10^9 (3)/25 = 7.2 xx10^8 N`

Explanation:

The force between 2 charged particles is

`F = K (q_1 q_2)/r^2` where
`q_i = "Charges of the particles", K = 9.0 xx 10^9 N*m^2/C^2`
Inserting the value of `q_1 = -3; q_2 = -1; r = (4- (-1)) = 5`
`F = 9.0 xx 10^9 (3)/25 = 7.2 xx10^8 N`
Note: The force between 1 coulomb charges separated by 5 meters is huge - roughly about a billion Newtons. What does this tell you?
Well the unit of Coulomb is pretty large, and for that size 5 meters separation generated and amazing (unrealistic amount of force)