Tensile strength is defined as a stress, which is measured as force per unit area. For some non-homogeneous materials (or for assembled components) it can be reported just as a force or as a force per unit width.
Answer Wiki. The practice of organizing to aggregate individuals' influence for economic reasons probably began with European craft guilds, although the master craftsmen were actually employers and capitalists. Trade unions or labor unions originated in England in the 1700s, but were outlawed until the 1800s.
Why Are Labour Unions Needed? Why Unions Are Still Needed. Labour unions formed in the 19th century as a response to wage and time exploitation of workers and dangerous working conditions. Although many people take the 40-hour work week for granted, this standard was won through union efforts.