Physics help needed!

[Skiguy411]

A comet is in an elliptical orbit around the Sun. Its closest approach to the Sun is a distance of 4.6e10 m (inside the orbit of Mercury), at which point its speed is 9.3e4 m/s. Its farthest distance from the Sun is far beyond the orbit of Pluto. What is its speed when it is 6e12 m from the Sun? (This is the approximate distance of Pluto from the Sun. The sun's mass is 2e30.

Anyone know where to start?

 

[hypn0tik]

Conservation of Energy

 

[skimple]

You need to determine the equation describing the ellipse of the orbit.

 

[ActuaryTm]

Originally posted by: Skiguy411
Anyone know where to start?

The Sun is a mass of incandescent gas...

 

[Yossarian]

Originally posted by: ActuaryTm

Originally posted by: Skiguy411
Anyone know where to start?

The Sun is a mass of incandescent gas...

a gigantic nuclear furnace.

 

[iluvtruenos]

42

 

[EugeneChien]

Originally posted by: hypn0tik
Conservation of Energy

Ek + Ep = Ek' + Ep'

Ep = - GMm/R

plug in the numbers

 

[dopcombo]

conservation of angular momentum?

I think the formula for an ellipse is most important here.

Man, I used to know this stuff.... 5 years out of university and i don't remember ******...

 

[hypn0tik]

Originally posted by: dopcombo
conservation of angular momentum?

I think the formula for an ellipse is most important here.

Man, I used to know this stuff.... 5 years out of university and i don't remember ******...

Formula of an ellipse:

x^2/a^2 + y^2/b^2 = 1

For constants a and b.

 

[ethebubbeth]

Originally posted by: Yossarian

Originally posted by: ActuaryTm

Originally posted by: Skiguy411
Anyone know where to start?

The Sun is a mass of incandescent gas...

a gigantic nuclear furnace.

Where hydrogen is built into helium
At a temperature of millions of degrees