Which object would fall to the ground faster: a heavy mass or a feather? (Please correct my logic).

I know that both objects will fall to the ground at the same time b/c of acceleration due to gravity However, my logic does not correspond to this answer:
1. Upon drawing an FBD of the heavy mass and the feather, I realize that the only force acting on both is Fg.
2. If Fg = m g, then Fg of mass will be greater than the Fg of the feather.
3. Therefore, Fg = Fnet. Fnet is proportional to acceleration. If Fnet of mass is greater than Fnet of feather, then mass should accelerate faster to the ground than the mass.

What is wrong with my reasoning? Help! Thank you.

1 Answer
Jan 19, 2017

Heavy mass (for various reasons), however, in an ideal situation with no atmosphere, both object would fall at the same time.

Explanation:

Alright, so we know that gravity acts on every object in a uniform matter - objects fall at the same speed.

We also know that #F_"NET"# is the sum of all forces present that is acting on the object.

Now, here comes the confusing part... we must also take into account air resistance (the friction/drag component in an FBD).

Air resistance increases if the object has a large surface area and if the mass is considerably smaller than the other.

If we were to take the feather and the heavier object (let's say it's a rock) to the Moon, and drop them at the same time, they would fall at the exact same time. This is because there is no atmosphere on the Moon, just gravity.

The reason why the rock fell first is because it has a smaller air resistance than the feather.

Hope this helps :)