As the speed of a body approaches the speed of light, its mass approaches what?

More Questions:

What birds were traditionally used to detect dangerous gases in a coal mine?

What board game was invented by Charles B. Darrow during the Great Depression?

What was the date of the first day of the 21st century?

Who is credited with inventing the saxophone?

What slot on the back of an arrow's shaft keeps it on the bowstring?

Who satirized the threat of nuclear was in "The Butter Battle Book"?

What language gave us the word "alphabet"?

In which film did Kevin Costner make his directorial debut?

On the TV show "Cheers', what was Sam's nickname when he pitched for the Boston Red Sox?

What country provided most of the settings for "The Lord of the Rings" movies?

Which U.S. President ended his country's participation in the Vietnam War?

What country released the world's first Christmas postage stamp?

Who is Thomas John Woodward better known as?

What is the capital of Macedonia?

Ireland's River Shannon drains which basin?