# How do you calculate speed at an object's perihelion?

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For example: The orbit of Halley's Comet around the sun is a long thin ellipse. At its aphelion the comet is 5.40 x 10^12m from the sun and moves with a speed of 13.0 km/s. What is the comet's speed at its perihelion where its distance from the sun is 8.60 x 10^10m.

For example: The orbit of Halley's Comet around the sun is a long thin ellipse. At its aphelion the comet is 5.40 x 10^12m from the sun and moves with a speed of 13.0 km/s. What is the comet's speed at its perihelion where its distance from the sun is 8.60 x 10^10m.

##### 1 Answer

#### Answer:

(perihelion speed / aphelion speed ) = ( 1 + eccentricity) / ( 1

So, the comet's perihelion speed = 816 km/s, nearly.

#### Explanation:

Perihelion speed = (5.40 x 10^12 / 8.60 x 10^10) X 13 km/s

In the usual notation, v^2 =

The other results follow from this.

Perihelion distance = a (1