1. The problem statement, all variables and given/known data (a) Determine the electric field strength at a point 1.00 cm to the left of the middle charge shown in Figure P15.10. http://www.webassign.net/sf5/p15_10.gif That hard to read number is 3 cm. (b) If a charge of -3.50 µC is placed at this point, what are the magnitude and direction of the force on it? Magnitude N 2. Relevant equations E = Keq/r^2 3. The attempt at a solution I tried using the formula but was incorrect. E = 8.99e9(1.5e-6)/.003^2 I used 1.5e-6 for q because i thought you need to use the middle charge and i think the r is .003 m since from -2uC to 1.5uC its 2 cm but it say its 1 cm to the left of the middle charge so i thought i add the distance. For B i am not even sure how to do since i dont even understand how to do part a.