Let E = yax V/m at a certain instant of time, and calculate the work required to move a 3-C charge from (1,3,5) to (2,0,3) along the straight-line segments joining:
a) (1,3,5) to (2,3,5) to (2,0,5) to (2,0,3)
b) (1,3,5) to (1,3,3) to (1,0,3) to (2,0,3)
Note: answers should be a) -9 J, b) 0