1. The problem statement, all variables and given/known data An electron is released from rest 2.0 cm from an infinite charged plane. It accelerates toward the plane and collides with a speed of 1.0x10^7m/s. What is the surface charge density of the plane?The answer is 2.52×10−7 C/m^2 ! 2. Relevant equations v=d/t, d=0.5at^2, E=n/2*8.85x10^-12, F=ma=Eq 3. The attempt at a solution I don't know what to do with the velocity. I tried relating it to energy but got stuck.