1. The problem statement, all variables and given/known data A particle mass m is shot tangentially to the surface of a planet mass M radius R0 at 3/4 escape velocity. Determine the maximum radius the particle achieves from the center of the planet 2. Relevant equations Escape Velocity : √(2GM/r) Energy due to Gravity : -GMm/r2 F=ma Angular Force : F=mv2/r Conservation of Angular Momentum : L = r x p or L=mvr 3. The attempt at a solution Honestly - the beginning of the attempt is where I'm having the issue = I can't decide if I want to use conservation of energy, conservation of angular momentum. My thought process tells me alright, the particle is shot at a velocity v0 (3/4 escape velocity). This particle has a force acting upon it - the force due to gravity. I can picture exactly what happens to the particle. it won't be shot out fast enough to reach orbit, it reaches a maximum radius r, and then in a parabolic trajectory falls back down to the planet. Quite honestly - I feel like it should be a very simple solution, I just can't wrap my head around it. Perhaps a tip to start will give me the momentum to find the solution. Thanks!