Misc: Which is the longest river - not river system - in the U.S.A.?

Questions

Pink Floyd song : "I want to tell you a story/about a little man/if I can"?

Pink Floyd song: "You say the hill's too steep to climb"?

Pink Floyd: Besides drums, what else does Nick Mason collect?

Pink Floyd: David Gilmour's solo albums were self titled and this name.?

Pink Floyd: The "gang" in The Wall was symbolized by what tools?