The orbit of Halley's Comet around the Sun is a long thin ellipse. At its aphelion (point farthest from the Sun), the comet is 5.1 1012 m from the Sun and moves with a speed of 12.0 km/s. What is the comet's speed at its perihelion (closest approach to the Sun) where its distance from the Sun is 8.2 1010 m?

Answer 1

v=sqrt (GMs/r)

use the first set of data to find the constant sqrt (GMs)= r^2 v

vn =sqrt ((ro^2*vo)/rn)