3 ms·

If you like this kind of puzzle, you might enjoy "Thinking Physics" by Lewis Carroll Epstein. This one is right on page 10 of the 3rd edition.

• snissn 16y ago
  I wish that there was a universal credits system on the internet, and that I could purchase books by the page.
  • eru 16y ago
    Just use Google books (or something similar). It allows you to view certain pages. It's not optimal, though.