Jawaban:

Diketahui:

q1 = q2 = q3 = q4 = q

text F=k end text fraction numerator text q end text subscript 1 times text q end text subscript 2 over denominator text r end text squared end fraction text = end text k text q end text squared over text r end text squared text F end text subscript a text = end text open parentheses fraction numerator text q end text squared over denominator 4 text πεa end text squared end fraction close parentheses text x end text

Fab tegak lurus dengan Fad. Gaya Coloumb merupakan besaran vektor. Apabila terdapat vektor yang tegak lurus dan sudutnya 90º maka persamaan resultan sama dengan persamaan pada phytagoras.

text F end text subscript a b end subscript equals text F end text subscript a d end subscript text =F end text subscript 1 text = end text square root of text F end text subscript a b end subscript squared text + end text text F end text subscript a d end subscript squared end root

Karena jarak dan muatan semua sama, maka dapat dinyatakan

text F end text subscript 1 text = end text square root of text F end text subscript a b end subscript squared text + end text text F end text subscript a d end subscript squared end root text F end text subscript 1 text = end text square root of text F end text squared text + end text text F end text squared end root text F end text subscript 1 text = end text square root of text 2F end text squared end root text F end text subscript 1 text =F end text square root of text 2 end text end root text F end text subscript 1 text =k end text text q end text squared over text r end text squared square root of text 2 end text end root

Interaksi muatan antara muatan a dan muatan c menggunakan diagonal bidang dengan persamaan berikut:

text F end text subscript a c end subscript text =k end text fraction numerator text q end text subscript a times text q end text subscript c over denominator text r end text squared end fraction text F end text subscript a c end subscript text =k end text fraction numerator text q end text times text q end text over denominator open parentheses text a end text square root of 2 close parentheses squared end fraction text F end text subscript a c end subscript text =k end text text q end text squared over open parentheses text a end text square root of 2 close parentheses squared text F end text subscript a c end subscript text =k end text text q end text squared over text 2a end text squared

Gaya total pada titik a dapat dihitung sebagai berikut:

text F end text subscript a text =F end text subscript 1 text +F end text subscript a c end subscript open parentheses fraction numerator text q end text squared over denominator 4 text πεa end text squared end fraction close parentheses text x=k end text fraction numerator text q end text squared square root of 2 over denominator text a end text squared end fraction text +k end text fraction numerator text q end text squared over denominator 2 text a end text squared end fraction open parentheses fraction numerator 1 over denominator 4 text πε end text end fraction close parentheses text x=k· end text square root of 2 text +k end text 1 half text x= end text square root of 2 text + end text 1 half

Dengan demikian, jawaban yang tepat adalah D.

semoga membantu ;)