The ball can be thrown in any orientation, so the accelerometer orientation will change while the program is running.
So ? So what ? You don't really think it's possible to know which way it's oriented in flight do you ?
I mean, with the right software and the right computer, it might very well be since you know 1g z is up -1g z is upside down,
0 g z means it's 90 degrees off from "up" . Where the whole concept of what your proposing falls apart and makes the idea ludacrous is that while the acceleration of the ball STOPS the moment it leaves the pitchers hand so it is basically in a freefall
horizontally in the sense that while it does have velocity , it has no acceleration so all values will be zero except for the effects of gravity in the up / down axis (where "down" means point at the earth perpendicularly). So you see , if you have both feet firmly
planted on the ground and you hold the accelerometer in your hand (like it is shown on page 35) you DO know which way it is oriented. If you mount it on vehicle and that vehicle is NOT a sidewinder missile , then it is reasonably safe to assume that the
acceleration in the x axis is related to the motion of the vehicle and if you see acceleration in the y axis then you've just been
broadsided by someone while running a red light. If you slam into a brick wall you should see a very large negative spike in the x axis. It you hydro-plane on the freeway in heavy rain and go into a full 360 (like I did once), your heart will skip a beat but you will get really cool acceleration in both x & y , but nothing in z until you roll over....