I delight on your question and learn from Calzrhe's answer. I positioned my answer in a distinctive way. seem while an gadgets is shifting in a airplane and that i ask you to uniquely detrmine that airplane wherein that is shifting by utilising a vector what is going to you %. As Calzrhe says, a perpendicular course to the airplane looks teh handy way, yet there are 2 perpendiculars, so we've convention to stipulate ?Xr as v, the place ?, r and v are all vectors. Now coming on your 2nd question definite there is a few thing, quite yet another stressful vector in that course stated as angular momentum, Vector L defined as rXp, the place p is the linear momentum vector. by utilising figuring out like this we've have been given some form of analogous similarity between linear and angular action. in case you stretch the analogy too plenty then there are a number of stressful issues you will face. yet pl are not getting annoyed use it and attempt to relish teh annoyance. As Feynman says approximately QM take it with no attention that it works please do no longer ask why with the aid of fact no person knows it! Intricacies of physics initiate precise in classical Physics it self. you're saying no longer something is taking place in perpendicular course. ok, take rotating wheel on an axle carry the axle on your 2 palms. Wheel is rotating no longer something is taking place alongside the axle. Now attempt rotate the axle and sense which you come across project in balancing your self. So even with each little thing some thing is element is there in perpendicular course and that someting additionally facilitates the wheel to rotate because it rotates.