What Am I Riddles

Question: I am flat, I am sharp; but I cannot hurt you. What am I?

Question: Sun is rising, off we go! Who will win the daily race!? He leads, I lead, way to go I lead, he leads, equal pace... Back and forth we race whole day Who will win the daily race!? Sun is sinking, side by side we stay To a halt has come the chase. What am I?

Question: At first I'm in pieces, but you build me and I carry you, at night when your tired or sleepy or even drunk, what am I?

Question: I am the one thing that stays after fire , I am the one that choke liars and yet the wind is my foe, in the morning I’ll be gone! Who am I?

Question: I can be used to build castles,
but I crumble in your hands.
I can help a man see,
and am found all around the lands.

What am I?