The manager of a public beach wishes to display 10 square signs with announcements and advertisements posted on them. Each sign has a side length of 2 m. All signs must face west. He considers placing the signs either i) isolated and at a distance from each other or ii) on the same plane and such that their edges are in contact, thus forming a strip 20 m long. Determine the total drag force on the 10 signs, for both configurations, when there is a wind of 60 km/hr a) from west to east and b) from north to south. Which configuration would you recommend and why?

Contributed by Stavros Tavoularis, Department of Mechanical Engineering, University of Ottawa, Ottawa, Canada. Image from inspirationmv.com.