A charge of #1 C# is at #(3,-2)# and a charge of #-3 C# is at #( -4,-1) #. If both coordinates are in meters, what is the force between the charges?

1 Answer
Mar 5, 2017

Answer:

#5.4xx10^8N# attractive force.

Explanation:

The distance between them can be found by subtracting #x#'s and #y#'s and doing Pythagoras':

#r = sqrt((3--4)^2+(-2--1)^2) = sqrt50 = 5sqrt2#

The electrical force is given by

#F = k(Q_1Q_2)/r^2#

where #k~~9xx10^9# is Coulomb's constant, #Q# is the charges, and #r# is the distance which we just worked out.

Using the values we know,

#F = 9xx10^9 xx (1 xx -3)/(5sqrt2)^2 = (-2.7xx10^10)/50#

#=-5.4xx10^8N#

Since the charges are opposite, they are attractive, so even though the force has a negative symbol, that means they are pulling together, not pushing apart.