Three point charges +6.4e-6, +2.5e-6, and -3.6e-6 lie along the x axis at 0m, .015m and .055m. What is the force exerted on q2 by the other two charges? What is the force exerted on q3 by the other two charges?

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`+6.4xx10^(-6)` `+2.5xx10^(-6)` `-3.6xx10^(-6)`

`Q_1` ______`r_1` _________`Q_2`________`r_2`________ `Q_3`

.015m .055m

Let the above line be a positive x-axis and

`r_1`=0.015m, `r_2`=0.055m

(i) Force exerted on `Q_2` by the other two charges is the sum of the force of repulsion by `Q_1` and the force of attraction by`Q_3`.

`F_(12)=(kQ_1Q_2)/(r_1)^2`

(i) Force exerted on `Q_2` by the other two charges is the sum of the force of repulsion by `Q_1` and the force of attraction by`Q_3`.

`F_(12)=(kQ_1Q_2)/(r_1)^2`

`F_(12)=(8.99xx10^9xx6.4xx10^(-6)xx2.5xx10^(-6))/(1.5xx10^(-2))^2`

```=6.392xx10^2 N` to the right

`F_32=(kQ_3Q_2)/(r_2)^2`

`=(8.99xx10^9xx3.6xx10^(-6)xx2.5xx10^(-6))/(5.5xx10^(-2))^2`

`=2.67xx10^1 N` to the right

Resultant force on`Q_2=F_12 +F_32`

`=639.2+26.7=665.9 N`

(ii)Force exerted on `Q_3` by the other two charges is the sum of the force of attraction by `Q_1` & `Q_3.`

(ii)Force exerted on `Q_3` by the other two charges is the sum of the force of attraction by `Q_1` & `Q_3.`

``

`F_13=(kQ_1Q_3)/(r_1+r_2)^2`

`=(8.99xx10^9xx6.4xx10^(-6)xx3.6xx10^(-6))/(7xx10^(-2))^2`

`=4.22xx10^1 N`to the left

Resultant force on`Q_3=F_13+F_23`

`=-42.2-26.7`

`=--68.9` N to the left.

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