Physics

Problem

An astronomer observes a planet orbiting a star in an elliptical path. At the perihelion (closest point), the distance is

2 \times 10^{8}\,\text{km}

and the planet's speed is

60\,\text{km/s}

. At the aphelion (farthest point), the distance is

6 \times 10^{8}\,\text{km}

. Using the principle of conservation of angular momentum, determine the speed of the planet at the aphelion.