Question

Spherical insulating ball and a spherical metallic ball of same size and mass are dropped from the same height Choose the correct statement out of the following (Assume negligible air friction)

• A. Both will reach the earth's surface simultaneously.
• B. Insulating ball will reach the earth's surface earlier than the metal ball
• C. Metal ball will reach the earth's surface earlier than the insulating ball
• D. Time taken by them to reach the earth's surface will be independent of the properties of their materials

Answer 1

Answer: (B)

Insulating ball will reach the earth's surface earlier than the metal ball

Answer 2

When the insulating ball is dropped, it can become charged due to various mechanisms like triboelectric charging. This charge can cause ionization of the surrounding air molecules, leading to a buildup of charge around the ball. This can create an electrostatic repulsion between the charged insulating ball and the oppositely charged air molecules, effectively reducing the effective weight of the ball and causing it to experience slightly less downward force compared to the metallic ball.

As a result of this reduced effective weight, the insulating ball may experience a slightly smaller acceleration than the metallic ball. This would lead to the insulating ball taking a slightly longer time to reach the ground compared to the metallic ball.

$\text{So, the correct answer is (B) Insulating ball will reach the earth's surface earlier than the metal ball}$