An iron ball and a wooden ball of the same radius are released from a heigh ‘H’ in vacuum. The time taken to reach the ground will be

In a vacuum, the only force acting on a falling object is gravity, a condition known as free fall [2]. According to the principles established by Galileo and later formalized by Newton, the acceleration due to gravity (g) is constant for all objects regardless of their mass, size, or material [2]. While Aristotle previously theorized that heavier objects fall faster, Galileo's experiments demonstrated that the time of descent is independent of mass. In the absence of air resistance (vacuum), the equations of motion show that displacement depends only on acceleration and the square of time [2]. Therefore, an iron ball and a wooden ball of the same radius released from the same height 'H' will experience identical acceleration and hit the ground at exactly the same time. This phenomenon has been famously verified in modern vacuum chamber tests using objects as diverse as bowling balls and feathers.

Sources

1. [2] https://en.wikipedia.org/wiki/Galileo%27s_Leaning_Tower_of_Pisa_experiment