Comets travel around the sun in elliptical orbits with large eccentricities. If a comet has speed 2.3×10^4 m/s when at a distance of 2.7×10^11 m from the center of the sun, what is its speed when at a distance of 4.3×10^10 m.
I tried using v = ((G*M) / r) ^ 0.5, but I'm not sure if that will work with this problem.
The Attempt at a Solution
* I tried using conservation of angular momentum (per a tutor's advice), but didn't get the right answer
* I tried using Kepler's 2nd Law (area sweep) because the area that is swept out is the same all around the circle, but again no luck
* I tried using conservation of energy
* I used the equation that I listed above and solved for the mass of the comet by plugging in the 1st velocity and radius. Then I used the mass I came up with, along with the 2nd radius and solved for the velocity (v = 5.8*10^4 m/s). I inputted this answer into my online homework site, and it said that I was close, but not right.
Can someone please help me figure out where I went wrong??
Thanks in advance.