Two charges of # -7 C # and # -2 C# are positioned on a line at points # -9 # and # 7 #, respectively. What is the net force on a charge of # -3 C# at # -2 #?

1 Answer
May 30, 2016

Answer:

#color(green)(F_"net")=2.13*10^9" "N#

Explanation:

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#"force between "Q_A " and "Q_B" is":#

#color(blue)(F_1)=k((-7)*(-2))/7^2#

#color(blue)(F_1)=(14k)/49#

#"force between "Q_B " and "Q_C" is :"#

#color(red)(F_2)=k*((-2)*(-2))/9^2#

#color(red)(F_2)=(4k)/81#

#color(blue)(F_1)" and "color(red)(F_3) " are opposite directions"#

#color(green)(F_"net")=color(blue)(F_1)-color(red)(F_2)#

#color(green)(F_"net")=(14k)/49-(4k)/81#

#color(green)(F_"net")=(1134k-196k)/3969#

#color(green)(F_"net")=(938k)/3969#

#color(green)(F_"net")=(938*9*10^9)/3969#

#color(green)(F_"net")=2.13*10^9" "N#