**Until a falling object reaches "terminal velocity"** which is when the wind resistance against the object in free fall becomes great enough to cancel any further acceleration from gravity.

You see this when you drop a hammer and a feather. The hammer hits first even though the acceleration rate is exactly the same for both the hammer and the feather. The difference being the feather reaches treminal velocity almost instantly so acceleration rate stops while the hammer will continue to pick up speed for quite a long while.

In the absence of atmosphere the hammer and the feather will accelerate equally and hit at exactly the same time.

here is the famous test from the surface of the moon showing the feather and hammer falling and landing exactly the same time.

mikemoose55

If we are going to get that far into the details then this needs some clarification. Objects don't accelerate at 9.8 m/s² until they reach terminal velocity, and then discontinuously stop accelerating. The rate of acceleration follows from Newton's 2nd Law (

*F* =

*ma*), where

*F* is the weight of the object minus the aerodynamic drag, which is approximately proportional to the square of the air speed

*v*. So,

*a *=* (mg - kv²)/m *=* g - kv²/m*

where

*k *is the constant of proportionality in the form:

*k *=* ρcA/*2

where

*ρ* is the air density,

*A* is the effective cross-sectional area and

*c* is a geometric factor, which is approximately unity for a flat(ish) shape. So while the instantaneous initial acceleration of any object is g, it immediately starts to decrease for all

*v* > 0.

If we take the cross-sectional area of a

Mavic 2 to be about 25 cm x 25 cm (a conservative estimate including the propellers) and its mass to be 0.9 kg, and the and solve the resulting differential equation, we get the following acceleration, speed and distance as a function of time, which is actually quite consistent with observed falling Mavics.