A line of positive charge is formed into a semicircle of radius R = 57.8 cm, as shown in the figure below. (The figure is a semicircle above the x axis with angle θ measured from positive y axis centred at the origin) The charge per unit length along the semicircle is described by the expression λ(θ) = λ0cosθ. The total charge on the semicircle is 13.2 µC. (a) Calculate the value of the constant λ0. (b) Calculate the total force on a charge of 3.11 µC placed at the center of curvature. I did part a i found the answer 1.14e-05 C/m. but for part (b) i cant seem to setup the integral any help would be appreciated.