There are four cars starting at a point. The first car points north, the second one points east, the third one points south, and the last one points west. Each car moves in its respective direction at a particular speed: n km/h to the north, e km/h to the east, s km/h to the south, and w km/h to the west. After t hours, the position of the cars can be viewed as a quadrilateral from space. Determine the perimeter of this quadrilateral given the values of n, e, s, w, and t.