the top of early get frozen at place where the surrounding air is at a temperature of minus 20 degrees celsius what will be the temperature of the layer of water in contact with the lower surface of an ice block and at the bottom of the lake​

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.