WORK, ENERGY AND POWER

Motion and forces are interconnected, but they don't tell the complete story of physical change. Why does pushing a car for a longer distance have a greater effect than pushing it briefly? Why does a falling object gain speed? Why does a moving object eventually stop? These questions point to a deeper concept: energy. Energy is the capacity to do work, and work is the process of transferring energy. These concepts unify disparate phenomena and provide powerful tools for solving problems that would be intractable using forces alone. Energy comes in multiple forms—kinetic (energy of motion), potential (stored energy), thermal, chemical, and others—and transforms between these forms constantly. The conservation of energy is one of nature's most fundamental principles. This chapter explores work, different forms of energy, the work-energy theorem, conservation of energy, and power. Understanding these concepts reveals the deep unity underlying all physical processes.

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