Hi! The reason I am asking the following few questions, is because I want to understand the way rotational momentum works in certain cases, so I can apply to activities I do in real life (snowboarding, diving). My knowledge of this area extends as far as normal momentum, rotational momentum, moment of inertia, and centripetal force. Take for instance, a backflip. Very easy to do. You gain rotational momentum backwards by pushing off the ground, and then you jump up while you have that momentum. Then you control the speed of spin by extending/contracting your body. Easy. Same goes for a frontflip. 180-1080 - normal sideways spins. Very similar to backflip. You throw your hands (or your shoulders for a slower spin) all in one direction, while your legs are pushing off the ground in the opposite direction. When you gain the momentum, you jump up, and the result is you spin. You control the speed of spin by stretching your arms/legs out and contracting them. You can throw counter-rotation when landing by rotating your torso in the opposite direction (this is very important in snowboarding - so you can land it just right). Now I understand all that "simple" stuff. Now, as I've been advancing with snowboarding and diving, I am beginning to enter the "inverted spins" area, where you do things like bacfklip and 720 simultaneously. Now this is where I need help. I guess the first question is - can you say that an object can have multiple axises of rotation? Like a vertical and a horizontal axis? For instance - take a ruler. If you flip it and spin it at the same time - it seems that it has 2 axises. But if you take something less "ruler-like", such as a backpack, and try to do the same, it seems that you have only 1 messed up axis of rotation. But I guess this question is kind of dumb - it's like asking does an object that moves straight in diagonale have 2 velocities - forward and to the left, or does it have one - towards the corner. So I guess I answered my quesion myself. The next question is, how can your "sideways" rotation affect your "upside down" rotation. For instance, I've tried doing a frontflip 720 off the diving board. IF I just combine a frontflip and 720 - throw my body forwards and spin it sideways at the same time - everything seems to be fine. But if I spin my hand around WHILE IN THE AIR, I only seem to be able to do a 360. Whereas if I spin it in some other direction, I end up doing some crazy sideways-flip 1080... Like this is what's bugging me. For instance, I was watching this skiing competition. Those guys do like a double backflip 720, which means for every backflip they do 360 rotation sideways. The wierdest thing is that when they take off the jump, the ONLY throw their body backwards - they don't put ANY sideways spin into the jump at all. And then when in the air they "STEER" with their hands. And the commentator says "watch her control those spins with her hands". It seems to me that they take of as if they were going for a normal double backflip, but then they somehow use rotation of their hands to add 720 into the jump, WHILE in the air. This seems to kind of defy the laws of physics - but the fact is they do it. Another thing is a very popular "off-axis 720" spin, in both skiing and snowboarding. It's like they do a 720 spin, but their body is half way upside down... horizontal... when in the air. This also seems to defy laws of physics... It's like first they rotate 90 degress backwards and end up in "laying down" positon, while their body is spinning around, and then they rotate 90 degrees forward, back into standing position... THis has been bugging me for quite a while, and I'd be very thankful if somebody could give me some insight on this aspect of physics, or forward me to a resource that would help me.