a . What is the magnitude of farce between two negative point charges . one of - 2 x 10 C , the other of - 4 x 10- C, that are 4.3 x 10 m apart. b. A. 6.50 kq object is hung from the bottom end of a vertical spring fastened to an overhead beam. The object is set into vertical oscillations having a period of 2.25 s Find the force constant of the spring