A raindrop falling from a height h above ground attains a near-terminal velocity when it has fallen through a height (3/4)h. Which of the diagrams shown in the figure correctly shows the change in kinetic and potential energy of the drop during its fall up to the ground?
1. 2.
3. 4.  

(b) Hint: Apply the concept of conservation of mechanical energy.

When the drop falls first velocity increases, hence, the first KE also increases. After speed (velocity) is constant this is called terminal velocity, hence, KE also becomes constant. PE decreases continuously as the drop falling continuously.

The variation in PE and KE is best represented by (b).