What Am I Riddles

Question: Once you are in my sight, you are gone in a flash, and people tend to use me for cash. I am often used as a dire assist, and people often believe that I cause harm, when I am but its catalyst. What am I?

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?