Tennis Racket Theorem

A fascinating observation about the rotation of a tennis racket (or ping-pong paddle) is that the racket flips over if rotated freely about one of its primary axes. This is a result of Euler's Equations of Motion and the moments of inertia about the various axes being time-independent. The so-called "Tennis Racket Theorem" applies to the case where the moments of inertia about the principal axes are spaced: I1 ≪ I2 ≪ I3. The theorem states that rotations about axes #l and #3 are much more stable than about axis #2, even though I2 may be very close to I3 in value.

Category:

Education

Tags:

• Tennis
• Racket
• Tricks
• Twist
• Tennis Racket Theorem
• Rotation
• Physics

[sadoldpedant]

A bit embarrassing that you can't spell "principal".

[drdanku]

@sadoldpedant . . . I do know how to spell "principal" (see the description of the video) . . . I just made the simple mistake of using the similar sounding but different meaning "principle" instead when I made the title slides. And, once I realized the mistake after posting the video, I didn't feel like removing it, remaking it and reposting it. So, my mistake is out there in public for all to see, as you so generously pointed out.