Mass in special relativity what causes these particles to be termed "massless." However, even massless particles have a relativistic mass, which varies with their observed energy in various frames of reference, The invariant mass is the ratio of four-momentum (the four-dimensional generalization of classical momentum) to four-velocity: and is also the ratio of four-acceleration to four-force when the rest mass is constant. The four-dimensional form of Newton's second law is: The relativistic expressions for "E" and "p" obey the relativistic energy–momentum relation: where the m is the rest mass, or the invariant mass for systems, and "E" is the total energy. The equation is
Mass marketing Mass marketing Mass marketing is a market strategy in which a firm decides to ignore market segment differences and appeal the whole market with one offer or one strategy, which supports the idea of broadcasting a message that will reach the largest number of people possible. Traditionally mass marketing has focused on radio, television and newspapers as the media used to reach this broad audience. By reaching the largest audience possible, exposure to the product is maximized, and in theory this would directly correlate with a larger number of sales or buys into the product. Mass marketing is the opposite