Question

A drop of a liquid, of a given radius, falls vertically through a given viscous medium. The pair of graphs, that represent the variation of velocity (v), and acceleration (a) of the falling drop, with time, is the pair marked as pair

Answer 1

Correct option:  (4)

Explanation: 

As the drop falls vertically through the viscous medium, its velocity keeps on increasing with time. This, in turn, increases the viscous force acting on it so that its acceleration keeps on decreasing with time. When the viscous force becomes large enough to balance the net downward force, the acceleration of the drop becomes zero. Its velocity than remains constant (with time) at a value called the terminal velocity of the graph. 

This variation of velocity and acceleration, with time, is non–linear because of the non–uniform acceleration of the falling drop. The pair (D) shows the variations in their correct form.