Compute all parts of given problem:
Problem: A ball has mass 3.0 µg and charge -7 nC moves from point A to point B. It has the same speed at points A and B, and the work done by the electric field during the move is -1.9 mJ.
Part A: What is the change in electric potential energy of the ball?
Part B: What is the change in voltage between points A and B?
Rework your solution from the beginning and check each step carefully.