Chapter 21, Problem 16P

GO In Fig. 21-27a, particle l (of charge q₁) and panicle 2 (of charge q₂) are fixed in place on an x axis, 8.00 cm apart. Particle 3 (of charge q₃ = +8.00 × 10⁻¹⁹ C) is to be placed on the line between particles 1 and 2 so that they produce a net electrostatic force ${\stackrel{\to }{F}}_{3,\text{net}}$ on it. Figure 21-27b gives the x component of that force versus the coordinate x at which particle 3 is placed. The scale of the x axis is set by x_s = 8.0cm. What are (a) the sign of charge q₁ and (b) the ratio q₂/q₁?

Figure 21-27 Problem 16.