Fun Riddles

Question: My shallow hills are the faces of kings.
My horizon is always near.
My music sends men to the grave.
My absence sends men to work.

What am I?

Question: There are 100 prisoners lining up to go to jail. Each prisoner is wearing a hat that is either black or white. The prisoners don't know their own hat color, just the hat color of those in front of them in line (the first prisoner in line can't see anyone's hat and the last prisoner can see everyone's hat except their own). Starting from the back, one of the guards asks each prisoner what color their hat is. If they are correct they get to go free but if they are wrong they go to jail.If the prisoners get to discuss a plan, how can at least 99 of them be saved?

Question: What is brown or silver, has a head and tail but no arms or legs?

Question: I have a few points but we're not competing.
And I'll help you win when you're eating.

What am I?

Question: You fill up a bathtub with water and you have a teaspoon, tablespoon, and fourth cup. What is the fastest way to empty the bathtub?