Electric Potential (Conceptual question)

[Fizickstudent]

Homework Statement

To find "E" in an electrostatics problem when you are given the velocities and/or distance, you would use the formula E = Δv/d.

Given the information below to start out with, derive the equation E = Δv/d and explain what happens to the negative signs (where do they go and why) as you continue to derive the equation.

Given information:
ΔEp = -ΔEk
Δv/d = Eki - Ekf
Δv/d = -1/2mvf^2

Homework Equations

E = Δv/d

The Attempt at a Solution

For me to derive this equation any further to the equation E = Δv/d I will have to somehow get rid of that negative, I was just wondering, what happens to that negative?

 

[rl.bhat]

In the given problem delta v is not the change in velocity, but change in potential . Please go through the definition of electric potential at any point due to a charge.