Question

Two charges of `-1 C` and `-8 C` are positioned on a line at points `6` and `-4`, respectively. What is the net force on a charge of `-3 C` at `1`?

Answer 1

`approx 7.6 times 10^9 N`

Explanation:

You have not provided units for the distances , so they have been assumed to be in metres in the solution provided....in blue.

Always draw it first.

The force between 2 charges follows Coulomb's Law

`F = k (q_1 q_2)/r^2` where k is Coulomb's constant `k = 9 times 10^9 N m^2 C^(-2)`

In this case both forces on the -3C charge are repulsive forces as indicated by the green arrows

The net force, acting left to right is:

`F_("net") = k/(color(blue)(5)^2) ((-8*-3 ) - (- 1 *-3))`

`F_("net") = (21k)/(25) approx 7.6 times 10^9 N`