Question

Compare the motion of a ball dropped on mercury to that of a ball dropped on the surface of earth

Answer 1

If a same ball is dropped from equal heights from Mercury and Earth,

the ball dropped on Earth will reach the ground before the ball dropped on Mercury.

This is because while acceleration due to gravity on the surface of Earth is 9.8 m/s2 , it is only 3.7 m/s2 on Mercury so time taken will be more than that taken on Earth.