# Electrostatics Question

1. Feb 13, 2009

### electritron

1. The problem statement, all variables and given/known data

At each corner of a square of side there are point charges of magnitude Q, nQ, mQ, and 4Q (Fig. 16-52), where n = 5 and m = 2.

Figure 16-52 is here: http://www.webassign.net/giancoli/16-52alt.gif

(a) Determine the force on the charge nQ due to the other three charges.
? N at ?° counterclockwise from the +x axis (to the right)

(b) Determine the force on the charge mQ due to the other three charges.
? N at ?° counterclockwise from the +x axis (to the right
)

2. Relevant equations

3. The attempt at a solution
I have no idea how to solve these questions. Any help would be greatly appreciated!
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Feb 13, 2009

### Redbelly98

Staff Emeritus
What equation do you know of that relates force and charge?

3. Feb 16, 2009

### electritron

All I know is that the force on the charge 5Q due to the other 3 charges is:
F5Q=FQ+F2Q+F4Q

4. Feb 16, 2009

### Redbelly98

Staff Emeritus
That's a reasonable start.

There's a well-known equation for the force between 2 charges. It is very likely the very first equation taught to you when your class began studying electricity. (And, you would not be asked a question like this if you had not been given that equation.)

Can you look in your textbook, or review your class notes, and find the equation?