Question

Answer 1

\(\overrightarrow{E_{MA}}+\overrightarrow{E_{MB}}=\overrightarrow{0}\)

\(\Leftrightarrow\left\{{}\begin{matrix}E_{MA}=E_{MB}\\\overrightarrow{E_{MA}}\uparrow\downarrow\overrightarrow{E_{MB}}\end{matrix}\right.\Leftrightarrow9\cdot10^9\cdot\dfrac{3\cdot10^9}{MA^2}=9\cdot10^9\cdot\dfrac{\left|q_2\right|}{MB^2}\)

\(\Leftrightarrow\left|q_2\right|=1.2\cdot10^{12}\cdot MB^2\)

TH1: q1q2<0

=>M nằm ngoài đoạn AB

=>M sẽ nằm gần A hơn

=>MA+AB=MB

=>MB=5+10=15cm

=>q2=2,7*10^10(C)=27nC

TH2: q1q2>0

=>q2<0

=>M nằm giữa A và B

=>MB=5cm

=>|q2|=3*10^9

=>q2=-3*10^9(C)