A point charge of 3.0 nC with a mass of 4.0 g is moved from
x=1.0 m to 1.5 m in an electric field of 5.0 N/C with the same
direction as the motion of the charge. (a) How much work is done on
the charge by the electric force? (b) Assuming that the charge
started from rest, what is its speed at 1.5 m?