Question

A planet of mass m is in elliptical orbit around a star S. At a point P1, the distance between the planet and the star has its minimum value, r1 = 4.30 x 10 to the 10 m. At point P2, the distance between the planet and the star has its maximum value, r2 = 7.30 x 10 to the 10 m. At both points the planet is moving in a direction perpendicular to the radial vector from the star.
If the planet's speed at point P1 is V1 = 48.0 km per second, what is the planet's speed at P2? in km per second.