central forces-plz chek answer! hello... i have this question in my classical mechanics book and was wondering if some one could help me? the question says that there is a particle of mass "m" that is moving under an attractive central force F=k/r^5 where k<0 show that the particles orbit is circular and this particle aslo passes through the force centre? Answer) what i did was that i said that in order for the orbit to be circular, the minimum potential ebergy should be equal to the total energy at that point,, finding the equilibrium points, the only equilibrium point that made the potential energy minimum was r=0 and this value gave the minimum value of p.e as infinity....is this approach right! please help....also please tell me how do we know which central force leads to what kind of an orbit!! please replyn soon.. thanks!!