Question

The orbit of Pluto is elongated with an eccentricity of 0.25. What is the approximate ratio of Pluto's orbital speed at perihelion to its orbital speed at aphelion?

Answer 1

`sqrt (5/3)`

Explanation:

Use `v=sqrtmu((2/r)-(1/a))`, perihelion = `a(1-e)` and aphelion `= a(1+e)`.

Here e = 0.25, approximately.

Now, for any planet, the ratio of the speeds at perihelion and aphelion becomes

`sqrt((1+e)/(1-e))` and here it is `sqrt( 1.25/0.75)=sqrt(5/3)`.