1. The problem statement, all variables and given/known data I'm not sure how to set up the differential equation. I've got 2 point charges...both positive. One charge is fixed in position (0, -250m)...the other is travelling at an initial speed in the -x direction (10,000m, 0) with 0 acceleration. At time t=0, I calculated the force applied in the x and y direction on the moving charge...I know the acceleration, velocity, and position after 1 second using newton's motion equations. The acceleration and force is non-constant in this situation...it starts at say -5 m/s^2 and then at say t=8 seconds will be at -60 m/s^2...then at t=9...the force in the x-direction will decrease... and then the acceleration will start dropping...-55 m/s^2 and so on. This transition happens before the moving charge crosses the origin. Any help appreciated...thanks. Differential equation will involve: F = ma a = dv/dt I dont know how to set it up after this.