# Homework Help: Point charges

1. Jul 17, 2010

### pat666

1. The problem statement, all variables and given/known data
The four point charges, each of + 3.00 μC, are situated at the corners of a rectangle of length, b = 60.0 cm and width, a = 30.0 cm.

Find the magnitude and direction of the force on q2, due to the other charges.
Solved this but i needed someone to check it for me because its worth marks.

2. Relevant equations

3. The attempt at a solution
The force on Q_2 is 1.05N and the direction is 68.5 degrees

2. Jul 17, 2010

### graphene

i am not sure if anyone would work out the calculations and verify the result.
but if you show all your calculations, someone might check them.

this problem is pretty simple vector addition & you've got to be sure about your calculations.

3. Jul 17, 2010

### pat666

Hey graphene sorry I meant to put my procedure in... basically there is one force in the i direction and 1 in the j - both from a 3 uC charge. The one that is slightly difficult (not really but compared to the others) is the one that sits on the opposite corner and affects both the i and j cmpts. For this I found the radius using p's theorem and then found the force - then I split that up by Fcos(theta)i+Fsin(theta)j. then I added the i and j cmpts and resolved again. can you please tell me if this is right??? thanks

4. Jul 18, 2010

### graphene

yes, that's the way to do it.

5. Jul 18, 2010

### pat666

thanks graphene