Question

Which of the diagrams in figure correctly shows the change in kinetic energy of an iron sphere falling freely in a lake having sufficient depth to impart it a terminal velocity?

Answer 1

(b) is the correct grapgh

Answer 2

Answer:

B

Explanation:

When an iron sphere will fall freely in the lake, it will accelerate by the force due to gravity. Thus, then its velocity will increase continuously and the resistance due to water will cause a force called viscous force or the upthrust (in fluids) which opposes its motion. It is entirely dependent upon the velocity of object as to when the velocity increases, the upthrust also increases. Hence during the fall of sphere first its velocity increases and then becomes constant after some depth. This constant velocity is known as the terminal velocity, hence KE will become constant beyond this depth, which is best represented in the figure (b).