'Mach One" refers to the speed of what?

More Questions:

When was tennis player, Martina Hingis, born?

Of the 88 keys on a piano, how many are black?

What is traditionally broken at the end of a Jewish wedding?

What is the International Criminal Police Organization better known as?

Which literary bear got its name from a London railway station?

On the bank of which river does the Portuguese capital of Lisbon stand?

What is the colour of chlorophyll?

What was Bruce Hornsby's backing band?

Who was the male star of the 1997 film "Titanic"?

What composer founded the "Barking Pumpkin" record label?

The time-traveling scientist in the TV show "Quantum Leap" shares his name with what playwright?

Who is known as Slim Shady?

U2's David Evans is better known by which nickname?

Which Canadian city was originally called Bytown?

What year was the first "Harry Potter" novel published?