Previous editions of this book have been favorably received and adopted by multitude of colleges and technical schools. In this substantially revised seventh edition, major changes have been made to keep pace with the most recent concept, methods, and terminology. Although the english gravitional and cgs systems are still include, so as to provide familiarity with them, the text now use the SI as its fundamental units system. Many new problems have been include and many others have been revised in the interests of clarity and pedagogical value. The theory section of each chapter has been reexamined and revised where necessary to conform better with thw needs of present-day students.