- #1

lydia_y620

- 8

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## Homework Statement

Figure (

*a*) shows charged particles 1 and 2 that are fixed in place on an

*x*axis. Particle 1 has a charge with a magnitude of |

*q*1| = 19

*e*. Particle 3 of charge

*q*3 = +16

*e*is initially on the

*x*axis near particle 2.Then particle 3 is gradually moved in the positive direction of the

*x*axis. As a result, the magnitude of the net electrostatic force on particle 2 due to particles 1 and 3 changes. Figure (

*b*) gives the

*x*component of that net force as a function of the position

*x*of particle 3. The scale of the

*x*axis is set by

*xs*= 1.70 m. The plot has an asymptote of

*F*2,net = 0.8688 × 10-25 N as

*x*→ ∞. As a multiple of

*e*and including the sign, what is the charge

*q*2 of particle 2?

## Homework Equations

F = kq

_{1}q

_{2}/r

^{2}

## The Attempt at a Solution

As x --> ∞, the force on particle 2 comes just from particle 1, so the force from particle 1 is always 0.8688 x 10^-25 N because particles 1 and 2 are stationary.

When x = 0.85 for particle 3, the net force on particle 2 is 0, so the force from particle 1 must equal the force from particle 3.

This means that 0.8688 x 10^-25 = k(q2*16e)/0.85^2

Is this correct? Apparently my answer is incorrect after I tried solving for q2 in terms of e.

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