(2.17) A particle moves in a central eld FOP) : exp (E) , (157) 7'2 a, where k and a are positive. (a) Write the equations if motion and reduce them to the equivalent onedimensional problem. (b) Discuss the qualitative nature of the orbits. (c) Show that of the orbit is nearly circular, the apsides will advance approximately by twp/a per revolution, where p is the radius of the orbit