NOVA Online (click here for NOVA home)
Time Travel
Site Map

20 mph

No. The answer isn't 20 mph.

You need to consider the speed of the train as well as the speed of the ball.

Try again.

Sagan on Time Travel | Traveling Through Time
Timespeak | Think Like Einstein | Resources
Teacher's Guide | Transcript | Site Map

Editor's Picks | Previous Sites | Join Us/E-mail | TV/Web Schedule
About NOVA | Teachers | Site Map | Shop | Jobs | Search | To print
PBS Online | NOVA Online | WGBH

© | Updated November 2000

Support provided by

For new content
visit the redesigned
NOVA site