3. (2 points) The force exerted by an electric charge at the origin on a charged particle at a point (,y,z) with position vector r =(x,y,z) is E(r) = K where K is a constant.
(A) Find a scalar potential function for E.
(B) Find the work done as the particle moves along a straight line from (1, 9,0) to (2,6, 7)
Z
(2,6,7)
(1,9,0) f