5. (21.47 modified and with a little extra) Three negative point charges lie along a line as shown below. a) Find the magnitude and direction of the electric field this combination of charges produces at point P, which lies 6.00 cm from the -5.00 C charge measured perpendicular to the line connecting the three charges. b) What should you change the -5C point charge such that the electric field at P is zero? +12.00 C 8.00 cm 6.00 cm -5.00C 8.00 cm +12.00 C