# Guassian infinite sheet and charge with kinetic energy

by scholio
Tags: charge, energy, guassian, infinite, kinetic, sheet
 P: 160 1. The problem statement, all variables and given/known data two infinite sheets of charge (one positive, one negative) are arranged parallel to each other and separated by a distance of 2m. a charge of 3 microcoulombs is realeased at the positive plate. when it reaches the negative plate it has a kinetic energy of 0.6 joules. what is the electric field between the plates 2. Relevant equations electric field of charge sheet E = sigma/2(epsilon_o) where sigma = charge density, epsilon_o = constant 8.85*10^-12 energy U = 1/2 CV^2 where C is capacitance, v is electric potential C = Q/V where Q is charge, V is electric potential 3. The attempt at a solution do i assume sigma as constant? do i assume both sheets have the same electric field, so electric field between the sheets is the sum of the two? how does the energy play a role in determining the electric field, the equation for electric field is already specified, and can be solved in terms of constants, assuming sigma is constant too. if i use the energy and capacitance equation i get: U = 1/2[(Q/V)(V^2)] 0.6 = QV/2 i am not sure how Q, V relate to electric field, i'm lost actually... help appreciated
 Sci Advisor HW Helper Thanks P: 25,235 Yes, yes. Constant sigma. Constant E field. Now start throwing out equations you don't need. Don't stop too soon. You only need one.
 P: 160 still somewhat lost, i did find in actuality that using : U = 1/2[(Q/V)(V^2)] 0.6 = QV/2 V = 400000 volts when Q = +3*10^-6 coulombs but how does V relate to electric field E?