planet chacha has an elliptical orbit around the sun. Data indicates that the planet has a speed of 30 km/s during perihelion with a distance of 1.52 E 8 km from the center of the planet to its sun.

Question

planet chacha has an elliptical orbit around the sun. Data indicates that the planet has a speed of 30 km/s during perihelion with a distance of 1.52 E 8 km from the center of the planet to its sun. Find its speed during aphelion at a distance of 1.54 E 8km

Answer 1

Angular momentum is conserved and at aphelion and perihelion, the direction of motion of the planet is perpendicular to the direction of the radius. Therefore,

mr_pv_p = mr_av_a

You know 3/4 of the variables (mass drops out), solve for the 4th.

Good luck!