Given:
• q1 = +8.60 x 10⁻⁶ C
,
• q2 = +5.10 x 10⁻⁶ C.
,
• q3 = -3.30 x 10⁻⁶ C.
,
• d12 = 0.350 m
,
• d23 = 0.155m
Let's find the magnitude of the net force on q2.
First find the force on the charge 1 and 2:

Also for the force on charge 2 and 3, we have:

Now, the magnitude of net force on q2 will be:

Therefore, the magnitude of the net force on q2 is 7.08 N.
• ANSWER:
7.08 N