- #1

soccerj17

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**[SOLVED] Kinetic Energy of Charged Particle**

## Homework Statement

Particles A (of mass m and charge Q) and B (of m and charge 5Q) are released from rest with the distance between them equal to 0.9976 m. If Q=33e-6 C, what is the kinetic energy of particle B at the instant when the particles are 2.9976 m apart?

## Homework Equations

U=kq1q2/r

K=(mv^2)/2

ΔU+ΔK=0

F=ma

## The Attempt at a Solution

I solved for the potential energy at both distances using U=kq1q2/r to find Ui=49.0683 J and Uf=16.3299 J. Then I used conservation of energy to find K so K=Ui-Uf and got K to be 32.7384 J. But I'm not sure how to get just the kinetic energy of particle B. I tried to sum the forces and use Newton's third law to find acceleration to see if that would help but I don't know how to find it without knowing the mass. I'm not sure if maybe I have to do a ratio to find the energy? I don't know what to do.