An electron is a subatomic particle (m = 9.11 x 1031 kg) that is subject to electric forces. An electron moving in the +x direction accelerates from an initial velocity of +8.28 x 105 m/s to a final velocity of 1.64 x 106 m/s while traveling a distance of 0.0608 m. The electron's acceleration is due to two electric forces parallel to the x axis: = 8.68 x 1017 N, and , which points in the x direction. Find the magnitudes of (a) the net force acting on the electron and (b) the electric force .

(a)Use the Work  energy theorem :
W = ΔKE
Fnet * S = 1/2 * m (vf^2  vi^2)
Fnet * 0.0608 = 1/2 * 9.11 x 10^31 ((1.64 x 10^6 )^2  (8.28 x 10^5)^2)
Fnet = 1.5 x 10^17 N
(b) the electric force ;
Fnet = 8.68 x 1017  F
1.5 x 10^17 = 8.68 x 1017  F
F = 8.68 x 1017  1.5 x 10^17 = 7.18 x 10^17 N
W = ΔKE
Fnet * S = 1/2 * m (vf^2  vi^2)
Fnet * 0.0608 = 1/2 * 9.11 x 10^31 ((1.64 x 10^6 )^2  (8.28 x 10^5)^2)
Fnet = 1.5 x 10^17 N
(b) the electric force ;
Fnet = 8.68 x 1017  F
1.5 x 10^17 = 8.68 x 1017  F
F = 8.68 x 1017  1.5 x 10^17 = 7.18 x 10^17 N