Suppose four protons were at the corners of a square. The length of

each side of the square is 1.52 × 10–9 m. If q1 is on the upper right corner, calculate the magnitude and direction of the resultant force on q1.

Hey there. Thanks for posting, I have found this video, which is the same as the problem you have. Let me know if this helps—if not, I may have time to make a detailed lesson and video later on this week, when my schedule clears up.

The only difference is your charge is the charge of a proton, and sides are a different length. Otherwise, the same calculation.