Good Riddles

Question: Rarely touched but often held If you have wit, you'll use me well What am I?

Question: A horse jumps over a castle and lands on a man, then the man disappears. How was this possible?

Question: Look at my face, I am somebody. look at my back, i am nobody. What am I?

Question: What is the center of gravity?

Question: What has 3 feet but cannot walk?