A rock is dropped at the same instant that a ball at the same elevation?

Answer 1

Any object that falls on Earth, no matter its size, will fall at the same speed. Drop a rock and a ball and both will accelerate at the same rate. The only thing that would slow them down is air resistance.

Answer 2

Both the rock and the ball will fall at the same rate of 9.8 m/s^2 due to gravity. They will hit the ground at the same time if there is no air resistance.