[Sam Hill]

"Now, what if you dropped a canon ball and at the same time shot a similar canon ball out at a 90 degree angle. Which would land first?"

That's popularly called the "Monkey Ball" experiment. Galileo invented it.

And he showed that they land at the same time.

[phantomworker]

You're right. But why?

(Galileo was earlier than Newton though, right?)