Office Physics: The Swivel Chair

Most people look at offices and think, This place is totally lacking cool physics. No lasers, no microscopes. Just a bunch of desks, computers, and chairs. I've never given any tours of my office, but I have given several tours of my labs (if you ever want one, I'd be happy to give you a tour).

But today, during my first 15 minutes of my lunch break I decided to change this view. Surely there is some interesting physics going on even here in this dingy office. I looked around the room and was amazed by what I saw: A bunch of desks, computers, and chairs. Still a lame office. I turned around in my swivel chair to throw my orange peel in the trash can and my eyes were opened to one of the most wonderful objects in the office: The Swivel Chair.

So there I was, eating a delicious orange, thinking about the fiber that's found in the peal. It would be very healthy for me to eat, but I chose to throw it away like any self-respecting American would do. I also thought about how if I was on a mountain, starving in a snowstorm, I would have eaten every single bit of that orange. But thank God, I'm not stranded on a mountain.

So I turned my swivel chair so I could throw away the peal. Mid rotation, I realized that I was spinning way too fast! My heart pounded and my forehead started to sweat, thinking about how embarrassing it would be if I couldn't stop myself before ramming right into the divider. My coworkers would surely ridicule me for the rest of my life. It was at that moment, just in the nick of time, that I remembered a very important lesson I learned in physics 1: Conservation of Angular Momentum.

In times of survival, while the adrenaline is rushing, your brain operates much faster than normal. This was my situation. I was to become either Dwight Schrute or Jim Halpert (which is no different from a life or death situation). Faster than ever, my brain calculated how I could change my body so that I could slow down before disaster. The solution to the equation was to stick my legs out. I slowed down so that I could gently place my feet against the neighboring desk without disturbing anyone. I quietly dropped my orange peal into the can and carefully turned back to write about the experience.

Conservation of angular momentum says that angular momentum is conserved. Please don't be shocked. When you spin yourself in your swivel chair, you're giving your body angular momentum. Angular momentum is dependent on your moment of inertia and your speed of rotation. Since angular momentum is always conserved you can only trade off between moment of inertia and speed. If you want to spin fast, you must reduce your moment of inertia by bringing your legs inward. If you want to slow down, you must increase your moment of inertia by stretching your legs out.

Hopefully this tidbit of knowledge will save your life someday.