Free-Fall – Equations of Motion
Free-Fall
Imagine a rock dropping from the top of a cliff. How does it fall to the ground? In this section, you will learn about the motion of falling objects and why objects of different masses fall with the same rate when there is no air resistance.
The animations below show what happens to objects during free-fall. In the first example, the object falls straight down from some height.
In this example, the velocity of the ball increases by 9.81 m/s for every second of fall. Therefore the acceleration on the ball is -9.8 m/s2. Since this acceleration is caused by the gravitational pull of the Earth, it is called acceleration due to gravity. It is negative because it is speeding up in a negative direction.