vector problem with electricity :( Ok, so i am having problems with my vectors in two homework problems (or maybe i went wrong some where else)... #1) Four identical point charges (q = +10.0 µC) are located on the corners of a rectangle. The dimensions of the rectangle are L = 70.0 cm and W = 25.0 cm. Calculate the magnitude and direction of the net electric force exerted on the charge at the lower left corner by the other three charges. ok, so i drew a lovely picture of the rectangle with all three force vectors as repulsion. my work goes something like this: F1= 8.99e9 * 10e-6 ^2 / .025^2 = 1438N F2= 8.99e9 * 10e-6 ^2 / (.025^2+ .07^2) = 163N F3= 8.99e9 * 10e-6 ^2 / .07^2 = 183.5N Then made a vector table: F1 x components = 0 and y components = 1438N F2 x components = 163cos19.65= 153N y components...=54.7N F3 x components = 183.5 N and y = 0 I then added up the x to get Fx=337N and Fy=1493N then F= (337^2 + 1493^2) ^1/2 = 1530N (but thats wrong) but then i got the angle by taking hte inverse tan of 1493/337 = 257degrees and that is correct, so i dont really know why my force magnitude is worng.... and i have another problem on my hw that is similar and i keep getting it wrong too, so i think i am doing something wrong with my vectors... any ideas or help would be greatly appreciated. THANKS!!