Question

An artificial satellite orbiting the earth in very thin atmosphere loses its energy gradually due to dissipation against atmospheric resistance, however small. Why then does its speed increase progressively as it comes closer and closer to the earth?

Answer 1

When an artificial satellite orbits nearer to Earth, its potential energy is reduced because of the decreased altitude. If the overall energy of the system remains constant, this reduction in potential energy is compensated by an increase in kinetic energy. As a result, the satellite's speed increases. However, atmospheric friction causes a slight decrease in its satellite's total energy.