## Conceptual Physics (12th Edition)

See diagram. The gravitational force is shown as a solid line, pointing at the body being orbited. The force is resolved into 2 components, shown by the dotted lines. The force component along the direction of motion, tangent to the ellipse, is the dotted green component labeled $F_{T}$. It acts along the direction of the satellite's motion, and does work on the satellite to change its KE and its speed.