Answer
The rod will begin to accelerate but will slowly stop decreasing to reach a terminal velocity.
Work Step by Step
When the rod is stationary, the only forces acting on it are gravity and the normal force, which make the bar roll. However, since the induced emf is equal to $\mathcal{E}=Blv$, the magnetic force is $F=ilB$, where $i=\frac{\mathcal{E}}{R}$, so the force on the rod is equal to $F=\frac{B^2l^2v}{R}$. Therefore, as velocity increases, the force on the rod increases. This force reduces acceleration and eventually will cause it to reach a terminal velocity.
