1. The problem statement, all variables and given/known data There is a system of 3 bodies, consisting of the sun, the earth and a comet. When the comet is at perihelion it is at a distance half that of the earth's orbital radius. At this point it has a speed twice that of the earth's. Ignore the gravitational forces between the earth and the comet. What is the orbital speed of the comet when it crosses the earth's orbit (should be given in terms of Ve)? What is the angle at which the orbit's cross? Will the comet escape from the solar system, never to return? Where Ve is the orbital speed of the earth. 2. Relevant equations 3. The attempt at a solution By considering conservation of angular momentum, i get: [L] = [L of comet at earths orbital radius] = [L of comet at perihelion] [L] = [Re x mv] = [Re/2 xm2Ve] where Re is the radius of the earth, and the square brackets show it is magnitude we are considering. From this i get the perpendicular speed of the comet when crossing earths orbit with respect to the position vector r as Ve. But i want to know the tangential speed of the comet at this point. Any ideas how to do this? I was told to use conservation of angular momentum and conservation of energy in working out this problem.