If a wave travels toward a barrier where the end is not fixed and reflects describe in either words or a drawing what the reflected wave will look like.
You can see in an animation what happens at:
http://www.kettering.edu/~drussell/Demos/reflect/reflect.html
There is an even better animation at
http://cnx.org/content/m13513/latest/
Set the "damping" adjustment at zero. You can see what the behavior of the
"fixed end", "free end" and "no end" cases look like