P22_051.PDF

51. The individual force magnitudes are found using Eq. 22-1, with SI units (so a =0 . 02m)and k as in

Eq. 22-5. We use magnitude-angle notation (convenient if ones uses a vector capable calculator in polar

mode), listing the forces due to +4 . 00 q ,+2 . 00 q ,and

−

2 . 00 q charges:

(4 . 60

10 − 24

180 ◦ )+(2 . 30

10 − 24

−

90 ◦ )+(1 . 02

10 − 24

−

145 ◦ )=(6 . 16

10 − 24

−

152 ◦ )

Therefore, the net force has magnitude 6 . 16

10 − 24 N and is at an angle of

152 ◦ (or 208 ◦ measured

counterclockwise from the + x axis).

−