- Which is the weakest of the four fundamental forces?
- What does a light year measure?
- What fell from a tree and contributed to Isaac Newton's theory of gravitation?
- How many times "hectopascal" is greater than "pascal"?
- What is momentum?
- If you sat on a fast train facing back of that train and it suddenly stopped - what would happen?
- Who built the first electric motor?
- Who discovered and began systematic study of the spectral absorption lines?
- Who discovered infrared radiation?
- Who is the author of general relativity theory?