Compute the work required to stretch a spring from 6 to 13 cm past equilibrium, assuming that the spring constant is =180 kg/s2.

Can someone explain to me how to do this problem ?

Photons with the highest energy have the longest period

Four objects each with charge +2.0×10−7c are located at the corners of a square whose sides are 2.0 m long. part a what quantities can be determined using this information? check all that apply. the electric force on a charged object placed at the center of the square. the mass of each object. the total electric potential energy of the system consisting of the four charged objects. part b find the electric force on a charged object placed at the center of the square.