1. The problem statement, all variables and given/known data You wish to put a 1000-kg satellite into a circular orbit 300 km above the earth’s surface. How much work must be done to the satellite to put it in orbit? 2. Relevant equations Conservation of energy 3. The attempt at a solution I don't need help answering the question because this is solved in my book. I'm confused about the calculation of work. My book solves it by using the change in total mechanical energy. Earlier in my book, it defined work as a change in kinetic energy or a negative change in potential energy. Why is it now a change in total mechanical energy?