FUN 1d motion prob--help 1. The problem statement, all variables and given/known data The figure (http://img471.imageshack.us/my.php?image=picprobfd5.png) shows a general situation where a stream of people attempt to escape through a door that is closed. The people move toward the door at a speed of v = 3.50 m/s, are each d = .25 m in depth, and are separated by L = 1.75m. The arrangement in the figure occurs at t = 0. a.) at what average rate does the layer of people at the door increase? b.) at what time does the layer's depth reach 5 m ? 2. Relevant equations The picture I drew is exactly like the one in the book. 3. The attempt at a solution I relly have no idea how to start, but it is the 1d motion section of fundamentals of p. Thank you.