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 #?

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Answer 1 · 2016-10-14T18:23:36

#approx 7.6 times 10^9 N#

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.

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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#