(1)解： F=2F cosa qo =2Y4T6r3 F go b -X re(a2+b2）xNa2+b2 qOb Te,(a2+b2)32 1010×108×0.2 3.14×8.85×10-12x(0.05)32 =6.44×107N方向：沿x轴正方向 题号结束π q r 4ε 2 0 = Q 2× cosa π 2 q ε0 Q ( ) a × + = 2 b b 2 a + 2 b π q ε0 Q ( ) = b 2 a + 2 b 3 2 ×( ) = 10-10×10-8×0.2 3.14×8.85×10-12 0.05 3 2 Q q q b a x y o r a F F1 a F = 2F1cosa =6.44×10-7 N (1)解: 方向 题号 结束 :沿x轴正方向