posted by jaredd .
Consider a long charged straight wire that lies fixed and a particle of charge +2e and mass 6.70E-27 kg. When the particle is at a distance 1.31 cm from the wire it has a speed 2.30E+5 m/s, going away from the wire. When it is at a new distance of 2.71 cm, its speed is 3.10E+6 m/s. What is the charge density of the wire?