(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A +35[tex]\mu[/tex]C charge is placed 32 cm from an identicle +35[tex]\mu[/tex]C charge. How much work would be required to move a +.5[tex]\mu[/tex]C test charge midway between them to a point 12cm closer to either of the charges?

2. Relevant equations

Wext = -qV

V = kQ/r

3. The attempt at a solution

Q= +35[tex]\mu[/tex]C, q = +.5[tex]\mu[/tex]C

I found the initial V, Vi = 2KQ/.16 and then the final V, Vf = KQ[1/.28 +1/.04]

Then I did W = -q(Vf-Vi) and got -2.5J

However, the answer is +2.5 J. This makes sense that the answer is positive- you're moving a + charge from an area of lower to higher potential. Why doesn't this agree with my formula though?

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# Homework Help: Work to move a charge

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