Which will fall faster?

Question

Do both heavy & light objects fall at same velocity? Isn't heavier objects have greater pull, according to law of gravitation?

Possible duplicate of Don't heavier objects actually fall faster because they exert their own gravity? — OrangeDog, Oct 11 '17 at 18:19
Fall at the same velocity under what conditions? Do you mean exactly the same velocity, or approximately the same velocity? These questions have very different answers (though I think most of this is covered in the question orange dog linked anyways). — JMac, Oct 11 '17 at 18:24

score 1 · Answer 1 · edited Oct 11 '17 at 20:04

Objects fall at a same rate; that means all objects close to the surface of the Earth fall with constant acceleration (g=9.8 m/s^2) NOT velocity.

Here are few important things to consider :

If the only force acting on the falling object is gravity and the drag force is negligible then using Newton's second law F=ma, you'll have $$\text{Force of gravity} = m a \to mg=ma$$ and as you can see from this equation $m$(mass) will cancel from both sides of the equation and you're left with $a=g$. Therefore, all objects should fall with the same acceleration g= 9.81 m/s$^2$.
If the drag force is not negligible then you will have $$mg-D=ma,$$ where $D$ is your drag. Then depending on strength of the drag force objects can fall at different rates.
$g$ can vary from place to place. In general g= 9.80621 -0.026$\cos(2\phi ) - 0.003 h$ m/s$^2$ where $\phi$ is geographical latitude and $h$ is elevation above sea level.

score 0 · Answer 2 · answered Oct 11 '17 at 19:32

Yes, heavier objects feel a larger pull from gravity.

But heavier objects are also harder to accelerate.

These two effects balance each other out - objects of double mass, feel a doubled pull from gravity but also resist this pull twice as much (due to Newton's 2nd law). In the end it balances out and the result is always a fall with $9.82\;\mathrm{m/s^2}$.

Which will fall faster?

2 Answers2