Answer:
B. 3v/4L
Explanation:
The total angular momentum is conserved. The angular momentum of the sphere is equal to its linear momentum times the distance from the pivot point. The angular momentum of the sphere-rod system is equal to the combined moment of inertia times the angular velocity.
MvL = Iω
MvL = (ML² + ⅓ ML²) ω
MvL = ⁴/₃ ML² ω
v = ⁴/₃ L ω
ω = 3v / 4L