What Am I Riddles

Question: What force and strength cannot get through, I with a gentle touch can do, And many in the street would stand, Were I not a friend at hand.

Question: Black were are and much admired, Men seek for us if they are tired We tire the horse but comfort man, Tell me this riddle if you can.

Question: Black within and red without with four corners roundabout.

Question: I do good things, but one small push could be a horrid disaster! I am normally used for decoration now.

Question: I fly and never rest. What am I?