Atrain consists of 50 cars, each of which has a mass 6.8
x10^3 kg. the train has an acceleration of +8.0 x 10^-2m/s^2.
ignore friction and determine the tension in thecoupling a) between
the 30th and 31st cars and b) between the 49thand 50th cars.

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.