A small hard solid sphere of mass m and negligible radius is connected to a thin rod of length L and mass 2 \mathrm{~m}. A second small hard solid sphere, of mass M and negligible radius, is fired perpendicularly at the rod at a distance h above the sphere attached to the rod, and sticks to it. In order for the rod not to rotate after the collision, the second sphere should hit the thin rod at
Answer Choices
A. h=0
B. h=L / 3
C. h=L / 2
D. h=L
E. Any location L will work
