Our lives of sedentary parenting are numbered. Now that Cheeky's realized that a little bit of effort can result in forward thrust or centripetal force, she's started rehearsing for the Clown/Krump Battlezone. Like all objects with mass, however, she is subject to the same laws of Newtonian physics which govern marbles, asteroids, and frisbees. For example:
1) Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.
The application of this law is evident approximately 10 minutes prior to her being retrieved from her crib. It's during this hatching phase that she builds up the initial momentum (stored as potential energy until awakened by gas) which will carry her through to her next nap. It generally starts as simple shuffling around the crib, but develops into full drum corps routines, complete with kicking and thrown objects. Eventually her arms are a blur of movement, or she's twisting into full scorpion pose to retrieve the Times Metro section. Fortunately, we have deep wells of external force to apply when she tries propelling herself into the coffee table, and as long as I'm not distracted by Godzilla vs. Gigan or Jesus Christ Superstar (as I was today...daytime TV sucks) I can usually keep that motion within a confined space.
2) The relationship between an object's mass m, its acceleration a, and the applied force F is F = ma.
I've learned this the hard way. There's not a lot of mass in Cheeky's little hands, but there's an enormous amount of acceleration when she goes for my chest hairs or neck fat. She pounds her chest so hard I sometimes think she'll break a rib, and her kicks (especially when my crotch is in the vicinity) have the well-aimed precision of Ikken hissatsu. I can't wait for the day I get brained by a teething ring to the temple.
3) For every action there is an equal and opposite reaction.
This law is the most enjoyable to watch. For example, if your action is to roll onto your stomach, but you've never learned to roll back, then the reaction is ten minutes of struggling and grunting while the only thing you can see is a stuffed giraffe or a table leg 3 inches from your face. The time would be shorter if your parents weren't amused enough to watch it for that long. If your action is to squirm out of our arms onto the couch, then the reaction is the pillow falling onto your head when you hit the cushion with a resounding "poof" sound. Unfortunately, this law applies to events which happen to her, so if my action is to toss Cheeky into the air, the reaction is to be doused with metabolically altered applesauce.
God help us if we ever have to put Cheeky in one of these....