In this lecture, we consider the problem of a body in which the mass of the body changes during the motion, that is, m is a function of t, i.e. m(t). Although there are many cases for which this particular model is applicable, one of obvious importance to us are rockets. We shall see that a significant fraction of the mass of a rocket is the fuel, which is expelled during flight at a high velocity and thus, provides the propulsive force for the rocket
A matrix is a rectangular array of numbers. A matrix with m rows and n columns is called an m × n matrix. The plural of matrix is matrices. A matrix with the same number of rows as columns is called equal if they have the same number of rows and the same number of columns and the corresponding entries in every position are equal
II. Listening Skills Listening to People talk about health 1. M: I haven't been to see my doctor for a very long time. I'm worried that he'll be angry with me for not having a physical examination for so long w: Which is more important, the doctors feelings or your health? Youd better go if you want to make sure everything is all right with you. It seems that the man worries more about the doctor's feelings than his own healtl