You're conducting a physics experiment on another planet. You drop a rock from a height of 1 m and it hits the ground 0.4 seconds later. What is the acceleration due to gravity on this planet?

First, we must assume that the planet has no atmosphere, so there's no air resistance,

and the behavior of the rock is the result of gravity and nothing else.

The formula for the distance covered by anything that accelerates from rest is

D = (1/2) (acceleration) (time) ²

In this problem, we're given the distance and the time, and we want to find the acceleration.

1 = (1/2 acceleration) x (0.4) ²

0.4² = 0.16

1 = (1/2 times 0.16) (acceleration)

1 = 0.08 acceleration

Acceleration = 1/0.08 = 12.5 meters per second²

That's about 27% greater than Earth's gravity.