Solution
= Solution
A central potential is $V(r)$. Then $\dot L=x\times(-\nabla V)=0$. Since $L\cdot x=0$, the trajectory lies in the fixed plane perpendicular to $L$.
= Solution
A central potential is $V(r)$. Then $\dot L=x\times(-\nabla V)=0$. Since $L\cdot x=0$, the trajectory lies in the fixed plane perpendicular to $L$.