Good Riddles

Question: Find the five digit number in which the first digit is one half of the the 4 fourth digit, the second digit is one fourth of the last digit, the fourth digit is 3 times the second digit, and the third digit is the first digit plus 4.

Question: I can be shared by many or spread to few, I am as fragile as silk yet as strong as steel. Wars have been fought in my name, generations defined by me. What am I?

Question: I can be seen and heard miles away, only show my position for a couple of seconds, but if touched it can kill you instantly.

Question: What looks like a duck but is red?

Question: If the ends justify the means, then what may be said about social media?