Whether you are a skydiver or a physics student, calculating the velocity and position of an object in free fall at various points in time can be a useful endeavor. Objects in free fall accelerate toward the Earth at the same rate, regardless of weight, unless there is a significant amount of air resistance present. Therefore, the only input needed to calculate position and velocity at any given moment is the amount of time the object has been in free fall.
Multiply the time in seconds that your object has been in free fall by 10 m/s2, an approximation for acceleration due to gravity on Earth. A closer approximation to the actual figure is 9.82 m/s2. This will give you the velocity of your object at a given time since free fall began. For example, after free falling for six seconds, an object has a velocity of (6 s times 10 m/s2) or 60 m/s.
Insert your time value into the equation d = 0.5 g x t2 to determine the distance that the object has fallen during that time. For example, after free falling for six seconds, the object has fallen a distance of (0.5 x 10 m/s2 x 6 s x 6 s) or 180 meters.
Multiply the result by 3.28 ft/m to convert the value from meters to feet.