A small steel ball is dropped into a long cylinder containing glycerine. Which one of the following is the correct representation of the velocity time graph for the transit of the ball?

According to Newton's second law, the net force on the ball is: $$ma = mg - F_b - 6\pi\eta rv$$

Initially, when the ball is dropped ($$v=0$$), the acceleration is at its maximum. As the velocity increases, the upward viscous drag also increases, which reduces the net force and causes the acceleration ($$a = \frac{dv}{dt}$$) to decrease over time.

Eventually, the upward forces balance the weight, and the acceleration becomes zero. At this point, the ball moves with a constant terminal velocity.

Among the given options, graph (B) accurately represents this behavior.