Variable-mass system events. The following derivation is for a body that is gaining mass (accretion). A body of time-varying mass "m" moves at a velocity v at an initial time "t". In the same instant, a particle of mass dm moves with velocity u. The initial momentum can be written as Now at a time "t" + d"t", let both the main body and the particle accrete into a body of velocity v + dv. Thus the new momentum of the system can be written as Since d"m"dv is the product of two small values, it can be ignored, meaning during d"t"
The Nature and Origins of Mass Opinion poorly informed, psychologically driven, and "mass-mediated" public opinion may be, it is capable of recognizing and focusing on its own conception of what matters. The Nature and Origins of Mass Opinion The Nature and Origins of Mass Opinion is a 1992 non-fiction book by political scientist John Zaller that examines the processes by which individuals form and express political opinions and the implications this has for public opinion research. The book has been called "the single most important book on public opinion since V. O. Key's 1961 classic, "Public Opinion and American Democracy"." Zaller argues that public opinion is heavily