Two charges of # -7 C # and # -2 C# are positioned on a line at points # -3 # and # 6 #, respectively. What is the net force on a charge of # -8 C# at # -2 #?

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Answer 1 · 2017-12-24T09:02:25

The force is #=+506.2510^9N#

The net force is

#F=k(q_1*q_3)/r_1^2+k(q_2*q_3)/r_2^2#

The charge #q_1=-7C#

The charge #q_2=-2C#

The charge #q_3=-8C#

The distance #r_1=-2-(-3)=1m#

The distance #r_2=6-(-2)=8m#

The constant #k=9*10^9Nm^2C^-2#

Therefore,

# F= 9*10^9 (((-7) *(-8)) / 1^2 + ((-8)*(-2)) / 8^2) #

#=+910^9(56+1/4)N#

#=+506.25*10^9N#

The #+# sign indicates that the force is repulsive.