What Am I Riddles

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

Question: I can be found all around the world I can be stricken but not feel it Both the moon and the sun know who I am I can be seen twice a day and 730 times a year What am I?

Question: When you don't have enough of me, you feel a kind of gloom. But when you are using me, it is time that you consume. What am I?

Question: Instruction manual, to and fro, if it’s wrong you'll still go - what is it?

Question: What can you touch but not see?