Halleys comet, which passes around the sun every 76 years, has an elliptical orbit. When closest to the sun (perihelion) it is a distance of 8.823 x 10^10m and moves with a speed of 54.6km/s. the greatest distance between haloes comet and the sun (aphelion) is 6.152 x 10^12m.
(a) is the speed of halleys comet greater than or less than 54.6 km/s when it is at aphelion? explain.
(b) calculate its speed at aphelion.