If h is not zero, the independent variable can be changed from t to ϕ d d t = ω ω d d φ φ = h r 2 d d φ φ giving the new equation of motion ∫ ∫ r F ( r ) d r = m h 2 2 [ ( − − 1 r 2 d r d φ φ ) 2 + ( 1 r ) 2 ]